Grade 2 Teacher's Edition - Chapters 1-6

Using the Book: pages 39-40 Cumulative Review Complete the number line. Fill in the sum. Do we have to regroup? Circle the correct sign. Subtract. Remember to start with the ones. 1. 48 + 40 = 88 1. 7 2. 3. 8 4. 40 P 8 12 P 6 9 P 9 12 P 8 7 48 88 O –2 3 O –2 5 O –4 7 O –5 6 2. 48 + 42 = 90 +42 59 44 45 31 40 +2 48 88 90 Circle to show in which tens the difference will be. 3. 48 + 43 = 91 +43 Complete the number line. Write the difference. 40 +2 +1 48 88 90 91 5. 9 0 – 4 = 8 6 86 90 70s 80s 90s Complete the number line. Write the difference. Reorder and add to find the sum. 1 6. 8 3 –2 –5 –5 78 80 4. 34 + 35 + 26 34 78 83 + 26 Reorder: 60 Write the value of each group of coins. 60 + 35 Compare. Write >, <, or =. 34 + 26 + 35 7. 95 Add to find the value of 3 quarters. 1 50¢ 50 ¢ = 50 ¢ 5. + 25¢ 25¢ 8. 25¢ + 25¢ + 25¢ + 25¢ Chapter 5 Lesson 18 50¢ 75¢ 22 ¢ < 35 ¢ End-of-Chapter Review 39 40 Now let’s practice some skills we’ve learned so far this year. Review each section together. For each section, read the directions and have the students For exercise 5 on page 39, remind the students that they need complete it on their own while you offer help as needed. to write the cent symbol when writing the value of coins.Copyright © by SPOTS Educational Resources. All rights reserved. solve this problem? [two] Why? [because we are subtracting solved in column form (one problem per card). Divide the from a two-digit number (83), and we need to subtract class into pairs. Give each pair a set of four index cards, and more than the ones that there are in 83; so first we need to have the partners work together to solve the problems on jump back to get to the tens number, and then we need to the cards. Then have some students share their work with jump back for the rest of the ones that we are subtracting] the class. [Solve on the number line together with the class. Elicit that first we need to jump back 3 to get to 80, and then we jump DIFFERENTIATED INSTRUCTION back the rest of the ones that we are subtracting (another 2) to get to the difference – 78.] Struggling learners: Some students may still have difficulty with a skill or skills taught this year. Have them Repeat with 30 – 5 and 47 – 9. partner with students who understand the skill(s) and work through a few exercises together. STUDENT TEACHER CLOSING STATEMENT: Prepare four types of index cards: 1) two-digit addition (with Today we reviewed some of the skills we’ve learned so sums up to 100) that can be solved on the number line; 2) two-digit addition (with sums up to 100) that can be solved far this year. Tomorrow we will begin Chapter 6! in column form; 3) two-digit subtraction that can be solved on the number line; and 4) two-digit subtraction that can be 39



Chapter 6 IntroductionIn Chapter 6 the students will further develop their math skills, as they learn how to calculatewith three-digit numbers.They begin their three-digit equations adventure with basic addition that requires no regrouping,using models (base-ten blocks), simple math drawings, and place-value charts to help them. Fromthere they progress to three-digit addition, regrouping only the ones. Solving these problems issimilar to adding two-digit numbers with regrouping – a skill with which they are already familiar.Before they move on to regrouping tens in three-digit addition, they will learn to regroup tens byadding two decade numbers with sums that are greater than 100, such as 80 + 70. This will helpthem better understand what it means to regroup 10 tens. Once they grasp this concept, it willnot be difficult for them to learn to regroup tens in equations such as 185 + 174.Finally, students will consolidate all that they have learned about three-digit addition, workingwith problems in which they will need to regroup both tens and ones.With the ongoing objective of strengthening students’number sense, Chapter 6 includes a lessonon adding four 2-digit numbers, giving the class practice in using the commutative property tofind the easiest way to add.Once students gain confidence in three-digit addition, they will move on to subtraction, usingmodels, simple drawings, and place-value charts to help them. First they will subtract withoutregrouping, and then they will regroup tens to subtract.Before they move on to regrouping hundreds when subtracting three-digit numbers, they willlearn about subtracting from 100. In order to subtract a decade number from 100 (e.g., 100 –40, 100 – 30, etc.), it is necessary to regroup the 1 hundred as 10 tens. Developing their skillsin this way gives students a very strong foundation and reinforces their understanding of theregrouping process.In subsequent lessons, students will regroup hundreds to subtract, then they will regroup bothtens and hundreds, then both tens and hundreds when there is a 0 in the tens place.At every stage, the students use models or simple drawings to help them clearly understandand internalize the concepts they are learning. In addition, in every lesson, the students willhave some problems to solve without any drawings but only with place-value charts, so thatthroughout the chapter they will be moving toward independence in three-digit addition andsubtraction.Please note that the Common Core Standards expect students at this stage to solve addition andsubtraction equations using models (a place-value chart is considered a model, since it helpskeep track of the addition or subtraction in three-digit equations). They are not expected to solvethese equations without using models.By the time students complete Chapter 6, they will have gained many new skills in addition andsubtraction of three-digit numbers.

Chapter 6 Lesson 1: Addition with Three-Digit Numbers INTRODUCTORY STATEMENT: [2 hundreds, 2 tens, and 3 ones] [Write “2 hundreds, 2 tens, We’ve learned to add two-digit numbers. Today we 3 ones” on the board directly below the first set of numbers.] will add three-digit numbers using base-ten blocks. Now let’s add. We start with the ones. How many ones are there in all? [8 ones] [Write “8 ones” in the sum.] How many tens in GOAL: all? [6 tens] [Write “6 tens” in the sum.] How many hundreds in all? [3 hundreds] [Write “3 hundreds” in the sum.] So, the Students will use models to add three-digit numbers. sum of 145 + 223 is 368. [Write 368 below the equation.] MATERIALS NEEDED: base-ten blocks (preferably Remember, when adding three-digit numbers always add one magnetic foam for the teacher, and basic base-ten place value at a time. Add the ones first; then add the tens; and models for the students); blank sheets of paper finally, add the hundreds.Common Core Standards: CCSS2.NBT.7 Repeat the process with 325 + 171 and 246 + 312. Use base- ten blocks to model the addition equation, and then write the addition shown by the blocks.LESSON WARM-UP STUDENT TEACHER:Review facts for fluency using the My Math Facts Divide the class into pairs. Distribute base-ten blocks topractice sheets. each pair. Write several three-digit addition problems (with no regrouping) on the board. Have each pair choose oneTHINKING TRIGGER problem to solve with base-ten blocks. Remind them to add the ones first. Circulate and offer help where needed. Call onWrite 53 + 22 and 353 + 122 on the board. Ask: What is the individual pairs to describe how they solved the problemsdifference between these two problems? they chose.CONCEPT DEVELOPMENT Copyright © by SPOTS Educational Resources. All rights reserved.I. Using models to add two-digit numbersWrite 43 + 25 in column form, and label the tens column andthe ones column. Say: We’ve learned to add two-digit numbersusing Dot Cards. Now let’s show how to add two-digit numbersusing the base-ten blocks. [Review the base-ten modelsthe class will be using by holding up one of each modeland asking what it represents (a flat represents 100; a rodrepresents 10; a cube represents 1).] Elicit how to show theproblem using the base-ten models. Solve together [68].II. Using models to add three-digit numbersSay: Now let’s add three-digit numbers using base-ten blocks tohelp us. [Show one flat, four rods, and five cubes.] These blocksshow one of our addends. How many hundreds, tens and onesare there? [1 hundred, 4 tens, and 5 ones] [Write “1 hundred,4 tens, 5 ones” on the board. Then show two flats, two rods,and three cubes.] These blocks represent our other addend.How many hundreds, tens and ones do the blocks show?22

Using the Book: pages 4735-4746 Addition with Three-Digit NumbXexrxs Add. 1. We can use models to help us add. 4 0 6 HTO Jack has 253 marbles in Hundreds Tens Ones his collection. +1 3 2 Hundreds Jane has 142 marbles in Tens Ones her collection. 5 3 8 How many marbles do Hundreds they have in all? Tens Ones Add. 3 9 5 2. 4 6 0 1. 3. 253 + 142 = 395 4. Hundreds Tens Ones 44 +4 3 2 Hundreds Tens Ones 8 9 2 Hundreds Tens Ones 2 3 4 4 5 1 Hundreds Tens Ones Hundreds Tens Ones +2 2 3 +3 2 2 Hundreds Hundreds Tens Ones Tens Ones 4 7 5 7 7 3 Hundreds Hundreds Tens Ones Tens Ones 2. 4 2 5 3 4 2 Hundreds Tens Ones Hundreds Tens Ones +1 0 3 +2 2 5 Hundreds Hundreds Tens Ones Tens Ones 5 5 2 8 6 7 Hundreds Hundreds Tens Ones Tens Ones Chapter 6 Lesson 1 2.NBT.1.a 43 Now let’s practice adding three-digit numbers using base-ten blocks. Always add the ones first; then add the tens; and finally, add the hundreds. DIFFERENTIATED INSTRUCTION CLOSING STATEMENT: Struggling learners: Some students may start adding Who can tell us what we learned today? the hundreds first, then the tens, then the ones. Remind Today we used base-ten blocks to add three-digit them to always start with the ones, because later, when numbers. Tomorrow we will draw models to help us they will need to regroup to add, they will have to start with the ones column. add three-digit numbers.Copyright © by SPOTS Educational Resources. All rights reserved. 23

Chapter 6 Lesson 2: Drawing to Add INTRODUCTORY STATEMENT: II. Drawing to add three-digit numbers Copyright © by SPOTS Educational Resources. All rights reserved.Yesterday we used base-ten blocks to add three-digit numbers. Today we will make simple math drawings Write 165 + 424. Say: This time, let’s make a simple drawing to help us find the sum. We’ll use squares to represent hundreds, to add three-digit numbers. vertical lines to represent tens, and dots to represent ones. [Draw the representations on the board as you describe them.] GOAL: How can we show the first addend, 165? [Draw the blocks on Students will draw models to help them add three-digit the board as students respond.] How many hundreds? [1 numbers. hundred] [Draw one square.] How many tens? [6 tens] [Draw MATERIALS NEEDED: six vertical lines to the right of the square.] How many ones? base-ten blocks (preferably magnetic foam); blank sheets [5 ones] [Draw five dots to the right of the vertical lines.] We of paper have 1 hundred, 6 tens, and 5 ones. Now let’s show the other addend, 424. How many hundreds? [4 hundreds] [Draw fourCommon Core Standards: CCSS2.NBT.7 squares aligned under the hundred of the first addend.] How many tens? [2 tens] [Draw two vertical lines aligned under LESSON WARM-UP the tens of the first addend.] How many ones? [4 ones] [Draw four dots aligned under the ones of the first addend.] Let’s add Review facts for fluency using the My Math Facts the ones. How many ones do we have in all? [9] [Write 9 in the practice sheets. ones column of the sum.] How many tens do we have in all? [8] [Write 8 in the tens column of the sum.] How many hundreds THINKING TRIGGER do we have in all? [5] [Write 5 in the hundreds column of the sum.] So, the sum of 165 + 424 is 589. If we don’t have base-ten blocks or other models, what can we use to help us add? III. PracticeCONCEPT DEVELOPMENT Write the equation 314 + 323 on the board. Ask volunteers to come up to the board and draw squares, lines, and dotsI. Using models to add three-digit numbers to show how to find the sum. The first student can draw the hundreds for the first addend, the second student can drawOn the board write 215 + 352 in a place-value chart labeled the tens, and the third student can draw the ones. RepeatH, T, O. Say: Let’s use base-ten blocks to find the sum. How many with three more students for the second addend. Togetherhundreds, tens, and ones are in the number 215? [2 hundreds, as a class, add the ones, tens, and hundreds as one more1 ten, and 5 ones] [As students answer, show two flats, one volunteer writes the sum in the equation.rod, and five cubes.] How many hundreds, tens, and ones arein the number 352? [3 hundreds, 5 tens, and 2 ones] [Show Repeat the process with 526 + 302, using simple maththree flats, five rods, and two cubes.] Now let’s add the base- drawings to represent base-ten blocks.ten blocks together to find the sum of 215 and 352. Whichplace do we start with? [the ones place] We have 5 ones plus STUDENT TEACHER2 ones. That equals…? [7 ones] [Write 7 as the sum in theones column of the equation.] We have 1 ten plus 5 tens. That Give each student a blank sheet of paper. Write the equationequals…? [6 tens] [Write 6 as the sum in the tens column 120 + 434 on the board. Ask students to make a simple mathof the equation.] We have 2 hundreds plus 3 hundreds. That drawing to add, then write the sum. Call on a volunteer toequals…? [5 hundreds] [Write 5 as the sum in the hundreds redraw his or her math drawing on the board. Fill in the sumcolumn of the equation.] So, the sum of 215 + 352 is 567. [Erase in the equation. Discuss some mistakes that can be made,the numbers and use the place-value chart as you work such as not lining up the columns, not adding the ones first,through the rest of the problems in the lesson.] and so on.24

Using the Book: pages 4757-4768 Draw more to add. Write the sum. Drawing to Add Make a simple math drawing to add. Write the sum. 1. H T O H TO 1. H T O HT O 351 432 +1 3 7 +2 4 3 488 675 2. H T O H T O 2. H T O HTO 235 250 +2 1 4 +2 1 6 549 466 3. H T O H T O Add. 4. H T O 5. H T O 304 3. H T O 657 589 + 34 +3 4 2 +4 1 0 341 338 +2 0 5 999 999 546 4. H T O H T O Let’s Review! Add. 426 6. 7. 8. 9. +1 2 3 1 1 1 1 529 46 37 52 68 +38 +26 +29 +27 84 63 81 95 Chapter 8 Lesson 2 2.NBT.1 45 46 Now let’s practice adding three-digit numbers by making represent hundreds, vertical lines to represent tens, and dots simple math drawings to help us add. We use squares to to represent ones. DIFFERENTIATED INSTRUCTION CLOSING STATEMENT: Struggling learners: Using and drawing models will Who can tell us what we learned today? Today we help students make the connection to understand that used simple math drawings to add three-digit num- the numbers they are adding represent ones, tens, and bers. Tomorrow we will use base-ten blocks to add hundreds. Some students may need extra practice using base-ten blocks to add before relying strictly on drawings three-digit numbers with regrouping ones. of the models.Copyright © by SPOTS Educational Resources. All rights reserved. 25

Chapter 6 Lesson 3: Three-Digit Addition: Regrouping Ones INTRODUCTORY STATEMENT: many tens in all? [9 tens] So, 56 + 37 = 93. Copyright © by SPOTS Educational Resources. All rights reserved. We’ve learned to add two-digit numbers with regrouping. Today we will learn to add Now let’s solve another problem, but this time let’s make a three-digit numbers with regrouping ones. simple math drawing to help us add. [Write 48 + 26 in column form, and elicit how to make a simple math drawing to show GOAL: the addends. Then add the ones.] Do the ones need to be regrouped? [yes] We will regroup 14 ones to make 1 ten and 4 Students will use models to add three-digit numbers, ones. Let’s show this. We circle 10 ones —­ all 8 ones from 48 and regrouping ones. another 2 ones from 26, and we draw a new ten. [Circle all 8 MATERIALS NEEDED: : base-ten blocks (preferably ones from 48 and 2 ones from 26; draw an arrow pointing magnetic foam for the teacher, and basic base-ten left, to the tens column, and draw a new ten above the other models for the students); blank sheets of paper tens.] How many ones are there now? [4 ones] [Write 4 in the ones place of the sum.] Let’s write a small 1 in the tens column toCommon Core Standards: CCSS2.NBT.7 show the new ten that we made. [Write a 1 in the tens column in the equation.] Now let’s add the tens. How many tens do we LESSON WARM-UP have in all? [7 tens] So, 48 + 26 = 74. Review facts for fluency using the My Math Facts II. Adding three-digit numbers with practice sheets. regrouping THINKING TRIGGER Write 229 + 147 in a place-value chart labeled H, T, O. Say: Now let’s add three-digit numbers. [Elicit how to make a simple On the board write 153 + 224 and 153 + 227. Ask: math drawing to show the addends.] First we add…? [the What is the difference between these two problems? ones] 9 ones plus 7 ones equals how many ones? [16 ones] Do the ones need to be regrouped? [yes] We will regroup 16 ones toCONCEPT DEVELOPMENT make 1 ten and 6 ones. Let’s show this. [Circle all 9 ones from 229 and 1 more one from 147; draw an arrow pointing left, toI. U sing base-ten models to add two-digit the tens column, and draw a new ten above the other tens.] numbers with regrouping How do we write the sum of the ones to show that we made a new ten? [We write 6 in the sum, because now there are sixOn the board write 56 + 37 in column form, with the columns ones.] [Write 6 in the ones place of the sum.] And we write alabeled Tens and Ones. Say: We’ve learned how to add two- small 1 in the tens column to show the new ten that we made.digit numbers with regrouping using Dot Cards. Now let’s see [Write a small 1 in the tens column in the equation.] Now wehow to regroup with base-ten blocks. [Draw a place-value add the tens. How many tens do we have in all? [7 tens] [Writechart. Elicit how to show each addend, and place the models 7 in the tens place of the sum.] Last, we add the hundreds.in the chart.] Which place do we add first? [the ones] 6 ones How many hundreds are there? [3 hundreds] [Write 3 in theplus 7 ones equals how many ones? [13 ones] Do the ones need hundreds place of the sum.] So, 229 + 147 = 376.to be regrouped? [yes] We will regroup 13 ones to make 1 tenand 3 ones. Let’s show this: We trade 10 ones (ten cubes) for 1 Repeat the process with 435 + 48. Elicit how to make a simpleten (one rod), and we put the ten in the tens place. [Remove ten math drawing to show the addends. Point out that there arecubes, and place a rod in the tens place.] Now let’s write the only ones and tens in 48, and no hundreds, so we will drawsum of the ones to show that we regrouped. How many ones only dots and lines for that addend. Solve together. Explainare there now? [3 ones] [Write 3 in the ones place of the sum.] that you are circling all 8 ones from 48 and another 2 onesAnd let’s write a small 1 in the tens column to show the new ten from 435 because we always add the greater number first.that we made. [Write a 1 in the tens column in the equation.]Now we add the tens. Remember, we need to include the new Repeat with 356 + 209. Elicit how to make a simple mathten that we made. We have 1 ten plus 5 tens plus 3 tens. How drawing to show the addends. Point out that there are only ones and hundreds in 209, and no tens, so we will draw only dots and squares for that addend. Solve together. Explain that you are circling all 9 ones from 209 and one more ones from 356 because we always add the greater number first.26

Using the Book: ppaaggeess4779--4880 3-Digit Addition: Regrouping Ones H TO 1. Add the ones. Circle the ones that form a new ten. Draw the new ten. Add. When the ones form 1 a new ten, fill in the 1. H T O new ten. 328 1 +1 4 7 2. Add the tens (including the new ten). 225 475 +8 3. Add the hundreds. 233 Circle the ones that form a new ten. Draw the new ten. Add. 2. H T O 1. H T O 1 1 139 +1 4 5 143 +7 284 150 Add. Regroup if necessary. 3. H T O 4. H TO 5. H T O 1 1 1 146 237 558 + 38 +2 0 3 +4 3 7 184 440 995 2. H T O Make a simple drawing to help you add. Solve. 1 6. Zach has 217 marbles in a jar. He gets another 104 marbles. How many marbles does Zach have now? 328 + 34 H TO 362 1 217 + +1 0 4 Zach has 321 marbles. 321 Chapter 6 Lesson 3 2.NBT.7 3-Digit Addition; Regrouping Ones 47 48 Now let’s practice adding three-digit numbers with regroup- ones, we regroup ten ones to make 1 ten, and we write a small ing ones. We start by adding the ones. If there are 10 or more number 1 above the tens column.Copyright © by SPOTS Educational Resources. All rights reserved. STUDENT TEACHER DIFFERENTIATED INSTRUCTION Divide the class into groups of four. Give each group base- Struggling learners: Remind students that when ten blocks, and then give each group a different addition counting on to add, they should always start with the equation (that requires regrouping ones) to solve, such as higher number. Use the problems in this lesson to 349 + 36, 562 + 109, 356 + 424, and so on. Write each equation emphasize why fluency with teen sums is important in a labeled place-value chart. Have the students in each (because when adding the ones, the sum will often group model the problem using base-ten blocks and then fill be a teen number). in the equation on the paper. When they are finished, have groups share their work with the class. Ask questions such as: CLOSING STATEMENT: Did the ones need to be regrouped? Why? Do you always have Who can tell us what we learned today? to regroup ones when adding three-digit numbers? Why did you Today we added three-digit numbers, regrouping write a small 1 in the tens column? ones. Tomorrow we will add tens with sums greater than 100. 27

Chapter 6 Lesson 4: Adding Tens: Sums Greater Than 100 INTRODUCTORY STATEMENT: 1 in the hundreds column to show the new hundred that we Copyright © by SPOTS Educational Resources. All rights reserved.We’ve learned how to regroup 10 ones when we add. made. [Write a 1 in the hundreds column in the equation.] We regrouped the 12 tens as 1 hundred and 2 tens because 12 Today we will learn how to regroup 10 tens tens is the same as 1 hundred and 2 tens. [Point to the numbers when we add. (1 and 2) that you just wrote.] GOAL: Now we add the hundreds. There is 1 hundred, so we will write a 1 in the hundreds place of the sum. [Write 1 in the hundreds Students will use models to add tens with sums greater place of the sum.] So, 70 + 50 = 120. [Erase the numbers and than 100. use the place-value chart as you work through the rest of the MATERIALS NEEDED: base-ten blocks (preferably problems in the lesson.] magnetic foam); blank sheets of paper Now let’s solve another problem, but this time let’s make aCommon Core Standards: CCSS2.NBT.7 simple math drawing to help us add. [Write 80 + 60 in column form, and elicit how to make a simple math drawing to LESSON WARM-UP show the addends. Then add the tens.] Do the tens need to be regrouped? [yes] We will regroup 14 tens to make 1 hundred and Review facts for fluency using the My Math Facts 4 tens. Let’s show this. We circle 10 tens – all 8 tens from 80 and practice sheets. another 2 tens from 60 – and we draw a new hundred. [Circle all 8 tens from the upper model and 2 tens from the lower THINKING TRIGGER model; draw an arrow pointing left, to the hundreds column, and draw a new hundred in the upper model.] Now let’s write Write 70 + 20 and 70 + 50 on the board. Ask: For which how we regrouped the 14 tens. How many tens are there now? problem do you think the sum is greater than 100? [4 tens] [Write 4 in the tens place of the sum.] Let’s write a small 1 in the hundreds column to show the new hundred thatCONCEPT DEVELOPMENT we made. [Write a 1 in the hundreds column in the equation.] We regrouped the 14 tens as 1 hundred and 4 tens. [Point to theI. Reviewing adding decade numbers numbers (1 and 4) that you just wrote.]Say: We’ve already learned to add decade numbers. Let’s review Now let’s add the hundreds. There is 1 hundred, so we will writethis skill. [Write 60 + 30 on the board.] Are we adding tens or a 1 in the hundreds place of the sum. [Write 1 in the hundredsones here? [tens] [Discuss the number of tens in each addend, place of the sum.] So, 80 + 60 = 140.and solve (90).]Repeat with 40 + 40. Repeat the process with 40 + 90. Elicit how to make a simple math drawing to show the addends. Solve together. PointII. Adding tens, with sums greater than 100 out that you are circling all 9 tens from 90 and another 1 ten from 40 because we always add the greater number first.Write 70 + 50 on the board in a place-value chart labeled Discuss how to write the sum of the tens, and that 13 tens isH, T, O. Say: Let’s find the sum using base-ten blocks. How many the same as 1 hundred and 3 tens.tens are there in 70? [7 tens] [Show 7 rods.] How many tens arethere in 50? [5 tens] [Show 5 rods.] First we add the ones. There STUDENT TEACHERare no ones, so I will write a 0 in the ones place of the sum. [Write0 in the ones place of the sum.] Let’s add the tens. How many Write 90 + 70 on the board. Divide the class into groups oftens are there in all? [12 tens] There are more than 10 tens, so three. Have one student in each group solve the problemwe will need to regroup; we will trade 10 tens for 1 hundred, and using base-ten blocks. Have another student make a simplewe’ll put the new hundred in the hundreds column. [Replace math drawing to find the sum. Have the third student write10 rods with 1 flat, leaving 2 rods.] Now let’s write how we the addition in column form and solve it by adding first theregrouped the 12 tens. How many tens are there now? [2 tens] ones, then the tens, and then the hundreds. Have everyone[Write 2 in the tens place of the sum.] And let’s write a small in the group compare their sums and discuss why all three methods work.28

Using the Book: pages 4891-5802 Adding Tens; Sums Above 100 When the sum has 10 or more tens, regroup 10 tens as 1 hundred. Fill in the blanks to solve. Circle the tens that form a new hundred. Draw the new hundred. Use the box to fill in the new hundred. Write the sum. 1. 80 + 80 H TO H TO 1 1 8 tens 80 70 + 8 tens + 80 + 50 160 12 0 70 + 50 16 tens = 1 hundreds 6 tens 0 ones 7 tens 2 tens 0 ones 2. 60 + 80 H TO + 5 tens 1 hundreds 6 tens 1 1 2 tens = + 8 tens 60 Fill in the blanks to solve. Circle the tens that form a new hundred. Draw + 80 the new hundred. Use the box to fill in the new hundred. Write the sum. 140 1. 90 + 30 H TO 14 tens = 1 hundreds 4 tens 0 ones 1 3. 90 + 70 H TO 9 tens 90 9 tens 1 + 3 tens + 30 + 7 tens 120 90 + 70 12 tens = 1 hundreds 2 tens 0 ones 160 2. 70 + 60 H TO 16 tens = 1 hundreds 6 tens 0 ones 7 tens 1 Add. Regroup if necessary. H TO 6. H T O + 6 tens 1 1 70 4. H T O 5. + 60 80 60 1 + 70 + 60 130 15 0 12 0 90 13 tens = 1 hundreds 3 tens 0 ones + 80 17 0 Chapter 6 Lesson 4 2.NBT.1 49 50 Now let’s practice adding tens with sums greater than 100. Trade 10 tens for 1 hundred, and put that hundred in the When there are 10 or more tens in the sum, regroup: hundreds column. DIFFERENTIATED INSTRUCTION CLOSING STATEMENT: Struggling learners: Some students may have difficulty Who can tell us what we learned today? Today we regrouping tens to make a hundred. Pair each of them added tens with sums greater than 100 by regrouping with a student who understands the process better. Give the pair one flat and at least 15 rods, and have one 10 tens to make 1 hundred. Tomorrow we will add partner write some problems of addition of tens (with three-digit numbers with regrouping tens. sums greater than 100) for the other partner to solve.Copyright © by SPOTS Educational Resources. All rights reserved. 29

Chapter 6 Lesson 5: Three-Digit Addition: Regrouping Tens INTRODUCTORY STATEMENT: sum.] Let’s add the tens. How many tens do we have in all? [13 We’ve learned to add three-digit numbers with tens] Do the tens need to be regrouped? [yes] We will exchange regrouping ones. Today we will add three-digit 10 tens for 1 hundred and add it to the hundreds place. How do we show this? [We circle 10 tens ­— all 8 tens from 280 and numbers with regrouping tens. another 2 tens from 150, and we draw a new hundred.] [Circle the tens, draw an arrow pointing left, to the hundreds GOAL: column, and draw a new hundred above the other hundreds.] Now let’s write how we regrouped the 13 tens. How many tens Students will use base-ten blocks to add three-digit are there now? [3 tens] [Write 3 in the tens place of the sum.] numbers, regrouping tens. And let’s write a small 1 in the hundreds column to show the new MATERIALS NEEDED: blank sheets of paper hundred that we made. [Write a 1 in the hundreds column in the equation.] We regrouped 13 tens as 1 hundred and 3 tens.Common Core Standards: CCSS2.NBT.7 [Point to the numbers (1 and 3) you just wrote.] LESSON WARM-UP Now let’s add the hundreds: 1 hundred plus 2 hundreds plus 1 hundred. How many hundreds in all? [4 hundreds] [Write 4 in Review facts for fluency using the My Math Facts the hundreds column of the sum.] So our sum is 430. practice sheets. Repeat as above with 457 + 281 and 432 + 394. Have volunteers THINKING TRIGGER come to the board and make a simple math drawing for each addend and show the regrouping of tens to form a new Write 153 + 74 on the board. Ask: How many hundreds hundred. Point out that, in every column, it’s always easier to are in the first addend? [1] How many hundreds do you add the greater number first. think will be in the sum? Why? STUDENT TEACHERCONCEPT DEVELOPMENTI. Reviewing adding tens, with sums greater Give each student a blank sheet of paper. Write 386 + 230 on the board. Have the students make simple math than 100 drawings to solve the number sentence. Invite some students to show their work to the class.On the board write 80 + 70 in a place-value chart labeledH, T, O. Elicit how to make a simple math drawing to show Copyright © by SPOTS Educational Resources. All rights reserved.the addends. Ask: How many tens are there in all? [15 tens] Dowe need to regroup? [yes] Why? [because there are or morethan 10 tens] [Elicit how to model the regrouping in the mathdrawing, and discuss how to write the sum of the tens. Pointout that 15 tens is the same as 1 hundred and 5 tens. Thenerase the numbers and use the place-value chart as you workthrough the rest of the problems in the lesson.]II. A dding three-digit numbers, regrouping tensWrite 280 + 150. To the right of the equation make a simplemath drawing, representing the first addend above and thesecond addend (aligned according to place value) below. Say:Let’s add the ones. There are no ones, so I will write a 0 in the onesplace of the sum. [Write 0 on the board in the ones place of the30

Using the Book: pages 8531-8524 3-Digit Addition: Regrouping Tens H TO 1. Add the ones. Circle the tens that form a new hundred. Draw the new hundred. Add. 2. Add the tens. When 1 1. H T O the tens form a new 1 28 0 hundred, fill in the + 60 new hundred. 262 3. Add the hundreds +1 5 4 34 0 (including the new hundred). 41 6 Circle the tens that form a new hundred. Draw the new hundred. Add. 2. H T O 1. H T O 1 1 374 36 0 +2 5 1 + 40 400 62 5 2. H T O Add. Regroup if necessary. 1 3. H T O 4. H T O 5. H T O 48 5 +3 6 0 1 1 1 84 5 272 352 583 +1 6 4 +2 5 5 +3 5 5 43 6 60 7 938 Make a simple drawing to help you add. Solve. 6. Rachel has read 180 pages. There are another 50 pages in her book. How many pages does Rachel’s book have in all? H TO 18 0 + + 50 Rachel’s book has 230 pages. 23 0 Chapter 6 Lesson 5 2.NBT.6 51 52 Now let’s practice adding three-digit numbers with the hundreds place, and we write a small number 1 in the regrouping tens. When there are 10 or more tens, we hundreds column to show that we regrouped. regroup: We trade 10 tens for 1 hundred and put it in DIFFERENTIATED INSTRUCTION CLOSING STATEMENT: Struggling learners: Some students may need practice Who can tell us what we learned today? Today we determining whether regrouping of ones or tens is need- added three-digit numbers with regrouping tens. ed when adding three-digit numbers. Give these students Tomorrow we will add three-digit numbers with four three-digit addition problems, one that requires regrouping of ones, two that require regrouping of tens, regrouping both tens and ones. and one that requires no regrouping. Have them look atCopyright © by SPOTS Educational Resources. All rights reserved. each problem and – without finding the sum – determine whether regrouping is needed. Then have them use base- ten blocks to see if they are correct. 31

Chapter 6 Lesson 6: Three-Digit Addition: Regrouping Tens and Ones INTRODUCTORY STATEMENT: II. Adding three-digit numbers, regrouping Copyright © by SPOTS Educational Resources. All rights reserved. We’ve learned to add three-digit numbers, both tens and ones with regrouping ones and with regrouping tens. Today we will add three-digit numbers with Write 367 + 165 on the board. To the right of the equation make a simple math drawing, representing the first addend regrouping both tens and ones. above and the second addend (aligned according to place value) below. Say: First let’s add the...? [ones] How many ones GOAL: are there in all? [12 ones] Do we need to regroup the ones? [yes] Why? [there are more than 10 ones] How do we show Students will use models to add three-digit numbers, this? [We circle all 7 ones from 367 and 3 more ones from regrouping both tens and ones. 165, and we draw a new ten next to the other tens.] [Circle MATERIALS NEEDED: base-ten blocks; blank sheets all 7 ones from 367 and 3 more ones from 165; draw an arrow of paper pointing left, to the tens column, and draw a new ten above the other tens.] How do we write the sum of the ones to showCommon Core Standards: CCSS2.NBT.7 that we made a new ten? [We write 2 in the ones place of the sum, because now there are two ones, and we write a LESSON WARM-UP small 1 above the tens column to show the new ten that we made.] [Write 2 in the ones place of the sum and a small Review facts for fluency using the My Math Facts 1 in the tens column in the equation.] We finished adding practice sheets. the ones; next we add the…? [tens] Remember that we need to include the one new ten. So we have 1 ten plus 6 tens plus 6 THINKING TRIGGER tens. How many tens in all? [13 tens] Do we need to regroup the tens? [yes] Why? [There are more than 10 tens] How do On the board write 238 + 157 in a place-value chart we show this? [We circle all 6 tens from 367 and 4 more tens labeled H, T, O. Ask: Will we need to regroup the ones or from 165, and we draw a new hundred next to the other the tens? How do you know? hundreds.] [Circle all 6 tens from 367 and 4 more tens from 165; draw an arrow pointing left, to the hundreds column,CONCEPT DEVELOPMENT and draw a new hundred above the other hundreds.] How do we write the sum of the tens to show that we made a newI. Review adding three-digit numbers, hundred? [We write 3 in the sum, because now there are regrouping ones, and regrouping tens three tens, and we write a small 1 in the hundreds column to show the new hundred that we made.] [Write 3 in theRefer to the problem from the Thinking Trigger (238 + 157) tens place of the sum and a small 1 in the hundreds column inthat is written on the board. Elicit how to make a simple math the equation.] We finished adding the tens; next we add the…?drawing to show the addends. Ask: How many ones are there [hundreds] 1 hundred plus 3 hundreds plus 1 hundred. Howin all? [15 ones] Do we need to regroup? [yes] Why? [because many hundreds in all? [5 hundreds] [Write 5 in the hundredsthere are more than 10 ones] [Elicit how to model the place of the sum.] So, 367 + 165 = 532.regrouping in the math drawing, and discuss how to writethe sum of the ones. Point out that 15 ones is the same as 1 Repeat with 452 + 259 and 253 + 387. For each problem,ten and 5 ones. Solve the equation together (the sum is 395). have six volunteers come to the board in turn to solve it: twoErase the numbers of the equation, and use the place-value to make simple math drawings for the addends; one to showchart as you work through the rest of the problems in the regrouping the sum of the ones in the drawing, one to showlesson.] how to represent the sum of the ones in the equation, andRepeat as above with 372+264. Point out that 13 tens is the finally, one to show regrouping the sum of the tens in thesame as 1 hundred and 3 tens. Solve together (the sum is drawing, and one to show how to represent the sum of the636). tens in the equation. Remind students that, in every column, it’s always easier to add the greater number first.32

Using the Book: pages 53-54 3-Digit Addition; Regrouping Tens and Ones H TO 1. Add the ones. When the Circle the ones that form a new ten. Draw the new ten. ones form a new ten, fill Circle the tens that form a new hundred. Draw the new hundred. Add. 11 in the new ten. 1. H T O 257 2. Add the tens When the 11 +1 6 4 tens form a new hundred, fill in the new hundred. 17 7 421 +1 4 6 3. Add the hundreds (including the new 32 3 hundred). Circle the ones that form a new ten. Draw the new ten. Circle the tens 2. H T O that form a new hundred. Draw the new hundred. Add. 11 1. 48 6 H TO +1 6 4 11 65 0 37 6 +2 3 7 3. H T O 11 61 3 35 9 2. +2 5 3 H TO 11 61 2 28 5 Add. Regroup if necessary. +1 5 5 4. H T O 5. H TO 6. H T O 440 11 11 11 Chapter 6 Lesson 6 54 8 67 3 49 5 +3 9 8 +1 4 9 +2 8 7 94 6 82 2 78 2 2.NBT.7 53 54 Now let’s practice adding three-digit numbers with small number 1 above the tens column; and when there are 10 regrouping both tens and ones. When there are 10 or more or more tens, we regroup 10 tens to make 1 hundred, and we ones, we regroup 10 ones to make 1 ten, and we write a write a small number 1 above the hundreds column.Copyright © by SPOTS Educational Resources. All rights reserved. STUDENT TEACHER DIFFERENTIATED INSTRUCTION Divide the class into pairs. Write 345 + 269 on the board. Struggling learners: Some students may tend to switch Have one partner explain to the other how to use base-ten the digits in three-digit addends; for example, they may blocks to model and find the sum. Have the other partner model 234 instead of 324. Have them underline each dig- write the problem on a sheet of paper and explain how to it in the addend as they model it, to be sure that they are add in column form. Then write 284 + 126 on the board and modeling the correct number of tens and ones. have the partners switch roles in explaining how to find the sum. CLOSING STATEMENT: Who can tell us what we learned today? Today we added three-digit numbers with regrouping both tens and ones. Tomorrow we will practice three-digit addition. 33

Chapter 6 Lesson 7: Practice: Three-Digit Addition INTRODUCTORY STATEMENT: addends. Discuss whether the sum of the ones or tens needs We’ve learned to add three-digit numbers with to be regrouped, and why or why not. Elicit how to show theregrouping both tens and ones. Today we will practice regrouping in the math drawing and in the equation. Solve all types of addition with three-digit numbers. together (the sum is 484). GOAL: III. Adding three-digit numbers, regrouping tens Students will practice adding three-digit numbers with and without regrouping. Write 455 + 174 on the board. Next to the equation, make a Materials needed: no materials are needed for this simple math drawing for each addend. Discuss whether the lesson sum of the ones or tens needs to be regrouped, and why or why not. Have two volunteers come up to the board, one toCommon Core Standards: CCSS2.NBT.7 show the regrouping on the math drawing and one to show the regrouping in the equation. Remind the class that we LESSON WARM-UP circle all 7 tens from 174 and 3 more tens from 455, since we always add the greater number first. Solve together (the sum Review facts for fluency using the My Math Facts is 629). practice sheets. IV. Adding three-digit numbers, regrouping both tens and ones THINKING TRIGGER Write 347 + 289 on the board. Have six volunteers come up Copyright © by SPOTS Educational Resources. All rights reserved. to the board in turn to solve it: two to make simple math Write 147 + 284 on the board in horizontal form. Ask: drawings for each addend, one to show regrouping the sum How do we write this problem in column form? Will we of the ones in the drawing, one to show how to represent regroup to find the sum? How do you know? the sum of the ones in the equation, and finally, one to show regrouping the sum of the tens in the drawing, and one toCONCEPT DEVELOPMENT show how to represent the sum of the tens in the equation and to solve the equation. Remind the class that, in everyI. Adding three-digit numbers without column, it’s always easier to add the greater number first. regrouping STUDENT TEACHEROn the board write 162 + 127 in a place-value chart labeledH, T, O. Ask two volunteers to come up to the board. Have one On the board, write in column form: 315 + 427, 543 + 271,make a simple math drawing to show 162, and have the other and 176 + 248. For each equation, discuss whether we needmake a simple math drawing to show 127. Review which to regroup tens, ones, or both, and then work together tocolumn we add first, which we add second, and which we find the sum of each equation. Ask: How was your work similaradd last, and discuss whether the sum of the ones and/or of for each problem? [In all three problems we first added thethe tens needs to be regrouped, and why not. Solve together ones, then the tens, then the hundreds.] How was it different?(the sum is 289). Then erase the digits of the equation, and [We regrouped different columns in each problem.]continue to use the place-value chart as you work throughthe rest of the problems in this lesson.II. Adding three-digit numbers, regrouping only the onesWrite 358 + 126 on the board. Ask two volunteers to comeup to the board and make simple math drawings to show the34

Using the Book: pages 55-56 Write the number sentence. Practice: 3-Digit Addition Add. Use the models to help. Add. Use the models to help. 1. H T O 1. H TO 1 1 35 7 +2 3 6 24 4 +2 3 7 59 3 48 1 2. 2. H TO H TO 34 3 11 +2 2 4 16 7 56 7 +1 5 5 3. 32 2 H TO 1 Add. Regroup if necessary. 24 6 3. 4. 5. H TO +1 3 6 H TO H TO 1 38 2 33 4 11 +1 5 3 42 7 38 6 +3 2 5 48 7 +2 5 4 75 2 64 0 Make a simple drawing to help you add. Solve. 4. 6. Ms. Lewis drove 76 miles last week. She drove 46 miles this week. H TO How many miles has Ms. Lewis driven in all? 11 H TO + 11 Ms. Lewis has driven 122 miles. 25 9 +2 5 3 76 + 46 51 2 12 2 Chapter 6 Lesson 7 2.NBT.7 55 56 Now let’s practice adding three-digit numbers. We will decide whether or not to regroup, and whether we need to regroup ones, tens, or both. DIFFERENTIATED INSTRUCTION CLOSING STATEMENT: Struggling learners: Remind the students that we can Who can tell us what we learned today? add in any order. Therefore, when adding the small 1 in Today we practiced adding three-digit numbers. the box above the tens or hundreds column, they can feel Tomorrow we will add four two-digit numbers. free to add it to the digit (the ten or the hundred) of eitherCopyright © by SPOTS Educational Resources. All rights reserved. the first or second addend, or they can add it after they’ve added the two digits in the tens or hundreds column in the equation. They can choose whichever order is easiest for them. 35

Chapter 6 Lesson 8: Adding Four Two-Digit Numbers INTRODUCTORY STATEMENT: II. Finding sums of four addends Copyright © by SPOTS Educational Resources. All rights reserved. We’ve learned to add with three two-digit numbers. Write 37 + 35 + 23 + 18 = ___ on the board. Say: Now let’s add Today we will add four two-digit numbers. four addends! Let’s see in which order to add, to make it easier to find the sum. Which ones-digits add up to ten? [7 and 3] So let’s GOAL: first add 37 + 23. [Cross off the numbers as you go along, to help keep track of what was already added. Write 37 + 23 in Students will use the commutative property and place column form, and add to find the sum (60).] Next we can add value to add four two-digit numbers. 35 to the sum. [Draw an arrow from the sum, 60, diagonally MATERIALS NEEDED: blank sheets of paper to the upper right, and write 60 (as the first addend) + 35 in column form. Solve together with the class (95).] Last, we addCommon Core Standards: CCSS2.NBT.6 18 to the sum. [Draw an arrow from the sum, 95, diagonally to the upper right, and write 95 + 18 in column form. Solve LESSON WARM-UP (113).] So, 37 + 35 + 23 + 18 = 113. [Fill in the sum in the horizontal equation.] Review facts for fluency using the My Math Facts practice sheets. Repeat the process with 56 + 52 + 47 + 28. THINKING TRIGGER III. Finding sums of four addends – another way Write 22 + 26 + 4 on the board in column form. Ask: What are some ways we can use to find the sum? Write 47 + 41 + 68 + 23 = ___ on the board in horizontal form. Say: Let’s add these four numbers another way. First, let’s findCONCEPT DEVELOPMENT two addends whose ones make a ten. Which two addends have ones that make a ten when they’re added together? [47 and 23]I. Finding sums of three addends [Write 47 + 23 in column form on the board. Ask a volunteer to come up to the board and show how to find the sum (70).]Write 9 + 21 + 9 on the board in horizontal form. Say: There Now let’s add the other two addends. [Write 41 + 68 on theare different ways to add three numbers. How can we add these board in column form. Have another volunteer show how tothree numbers? What numbers have digits in the ones column find the sum(109).] Now we can add the two sums. [Write 109that we can add first? [We can add 9 + 9 first, because it is a + 70 on the board in column form. Solve (179).] So, 109 + 70doubles fact that we know: 9 + 9 = 18. Then we can add the = 179. [Fill in the sum in the horizontal equation: 47 + 41 + 68third addend. Or, we can add 21 + 9 to make a ten – 30; and + 23 = 179.]then we can add the third addend.] Let’s add 9 + 9 first. [9 +9 = 18] What do we do next? [Add 18 + 21.] [Write 18 + 21 in Repeat the process with the equation 74 + 35 + 41 + 85.column form on the board.] What is the sum? [39] So, 9 + 21 Guide students to first find two addends whose ones make+ 9 = 39. a ten and add them (35 + 85 = 120); then add together theNow let’s add 21 + 9 first, since the ones make a ten. [Write 21 + other two addends (74 + 41 = 115); and finally, add the two9 in column form, and solve (30).] What do we do next? [Add sums (120 + 115 = 235). So, 74 + 35 + 41 + 85= 235.9.] [Draw an arrow diagonally from the sum (30) to the upperright, and write 30 (as the first addend) + 9 in column form.] STUDENT TEACHERWhat is the sum? [39] So, it doesn’t matter in what order we addthe addends; the sum will always be the same. Distribute a blank sheet of paper to each student. Write 55Write 39 + 16 + 31 on the board. Ask: In which two addends do + 27 + 43 + 71 = ___ in horizontal form on the board. Havethe ones make a ten when we add them together? [39 and 31] the students determine which two addends they will addLet’s add those two addends. [Write 39 + 31 in column form together first, write the addition problem, and find the sum.on the board. Solve together (70). Write 70 as the sum.] The Then have half the class add the other two addends and findsum is 70. Now let’s add the third addend to the sum. [Write the sum and afterward add the two sums together. Have the70 + 16 on the board in column form. Solve together (86).] other half of the class solve the equation by adding on theSo, 39 + 16 + 31 = 86. third addend to the sum of the first two, and then adding the fourth addend to the sum of the first three addends. Have36 students from the two groups compare methods, checking to make sure that the sum is the same regardless of the addition-method used.

Using the Book: pages 57-58rite the number sentence. Adding Four 2-Digit Numbers Add 36 + 75 + 42 + 54. You can add in any order. Here is one way. First find the sum of two addends. Then add the rest. You can add in any order. Find two addends Add the other Add the two sums. 1. 84 + 38 + 65 + 46 Addition sentences will vary. with ones that make two addends. a ten , and add them. H TO H TO H TO 11 11 The 6 in 36 and the 4 in 13 0 54 together make a 10. 84 65 +1 0 3 + 46 + 38 H TO H TO H TO 23 3 13 0 10 3 1 1 1 2. 71 + 35 + 55 + 64 36 75 117 + 54 + 42 + 90 H TO H TO H TO 1 1 1 90 11 7 207 35 90 16 1 First find the sum of two addends. Then add the rest. + 55 + 71 + 64 You can add in any order. Addition sentences will vary. 1. 63 + 28 + 77 + 41 90 16 1 22 5 3. Add to find the value of 4 quarters. H TO 11 H TO H TO H TO 25¢ + 25¢ + 25¢ + 25¢ H TO H TO 1 1 1 7 5¢ 28 5 0¢ + 2 5¢ 63 + 41 14 0 2 5¢ + 2 5¢ + 77 + 69 + 2 5¢ 1 0 0¢ 69 7 5¢ 14 0 20 9 5 0¢ 2. 54 + 37 + 25 + 66 LET’S WRITE! H TO H TO H TO Look at exercise 2. Which two addends did you add first? Explain why. 11 I added 35 + 55 first, because the ones of those 12 0 1 two addends (5 + 5) equal 10. 54 + 37 + 66 15 7 15 7 + 25 12 0 2.NBT.6 18 2 Chapter 6 Lesson 8 57 58 Now let’s practice adding four two-digit numbers. Remem- sums together. Or, after you find two addends that make a ten ber that you can add the addends in any order. It may be when you add them together, you can add the third addend to easier to find two addends that make a ten when you add the sum, and then add the fourth addend to that sum. them together, and add those two first. Then you can find As you go along, cross off the numbers you’ve already added, to the sum of the other two addends, and finally, add the two help keep track of what you’ve done so far. Repeat with 95 + 87 +79 + 65. Have the students switch CLOSING STATEMENT: methods, so that each half of the class solves it the other way. Today we added four two-digit numbers. DIFFERENTIATED INSTRUCTION Tomorrow we will subtract three-digit numbers.Copyright © by SPOTS Educational Resources. All rights reserved. Struggling learners: Students may need help with keep- ing track of which addends they’ve already added. Have students circle or cross off the addends as they go along. Some students may find it easiest to keep track of their work if they add on just one addend at a time, in the or- der in which the addends appear in the original equation. 37

Chapter 6 Lesson 9: Subtraction with Three-Digit Numbers INTRODUCTORY STATEMENT: are left? [2] [Write 2 in the tens column of the difference.] Now We’ve learned to subtract two-digit numbers. let’s subtract the hundreds. We’ll remove 1 hundred. [Take away Today we will subtract three-digit numbers one flat and place it on your desk.] How many hundreds are left? [1] [Write 1 in the hundreds column of the difference.] using base-ten blocks. So, 247 – 123 = 124. 124 is our difference. [Remember, when we subtract we always start with the ones. [Erase the numbers and GOAL: continue to use the place-value chart as you work through the rest of the problems in the lesson.] Students will use models to subtract three-digit num- bers. II. Practice MATERIALS NEEDED: base-ten blocks (preferably magnetic foam for the teacher, and basic base-ten Divide the class into pairs. Distribute base-ten blocks to models for the students); blank sheets of paper each pair. Write 564 – 242 = ___ on the board. Say: Let’s solve this together. Let’s show 564 with base-ten blocks. How manyCommon Core Standards: CCSS2.NBT.7 hundreds do we need? [5] How many tens do we need? [6] How many ones do we need? [4] [Circulate to check that the LESSON WARM-UP students are modeling the numbers correctly.] Let’s subtract using the base-ten blocks. We start with the ones. We remove 2 Review facts for fluency using the My Math Facts ones. How many ones are left? [2] [Write 2 in the ones column practice sheets. of the difference.] Now we remove 4 tens. How many tens are left? [2] [Write 2 in the tens column of the difference.] Finally, THINKING TRIGGER we remove 2 hundreds. How many hundreds are left? [3] [Write 3 in the hundreds column of the difference.] So, 564 – 242 = Tell this story problem: Mrs. Talbot made 247 sandwiches 322. for the school picnic. 123 of the sandwiches were eaten. How many sandwiches are left? [Ask:] Will you add or Write 468 – 234 on the board. Ask the pairs of students to subtract to solve? Why? use their base-ten blocks to find the difference. Circulate and provide help where needed. Have one pair of students show the class the steps they took to find the difference.CONCEPT DEVELOPMENT: STUDENT TEACHER:I. Using models to subtract three-digit Write several three-digit subtraction equations (with no numbers regrouping) on the board. Have each student choose one equation to solve using base-ten blocks. Call on individualSay: Today we will subtract three-digit numbers. Let’s use base- students to describe and show on the board how theyten blocks to help us find how many sandwiches were left after solved the problem they chose.the school picnic. [On the board write 247 – 123 in a place-valuechart labeled H, T, O. Then draw another, larger place-value Copyright © by SPOTS Educational Resources. All rights reserved.chart for models, and label the columns H, T, O. Display twoflats, four rods, and seven cubes in the chart.] What numberdo these models represent? [247, the number of sandwichesMrs. Talbot made for the school picnic] What number do weneed to subtract from 247? How many sandwiches were eaten?[123] Now let’s subtract. We start with the ones. We’ll remove 3ones. [Take away three cubes, and place them on your desk.]How many ones are left? [4] [Write 4 in the ones column of thedifference.] Let’s subtract the tens. We’ll remove 2 tens. [Takeaway two rods, and place them on your desk.] How many tens38

Using the Book: pages 59-60 Subtraction with Three-Digit Numbers We can use models to help us subtract. Cross off to subtract. Write the difference. 1. H T O Dan has 338 tickets H T O in his bin. 45 6 –2 2 4 He gives 214 tickets to his sister. 232 How many tickets 12 4 2. H T O does Dan have left? 338 – 214 = 124 59 38 7 –1 3 2 Cross off to subtract. Write the difference. 255 2. H TO 3. H T O 47 6 56 6 –1 3 2 –2 1 3 344 353 3. 2.NTB.7 4. H T O H TO 47 5 34 8 –2 3 5 –1 1 5 240 233 5. H T O Chapter 6 Lesson 9 34 7 –2 3 3 114 60 Now let’s practice subtracting three-digit numbers using Complete the first problem together with the class. Discuss models. how the models are crossed off to represent the subtraction process, and explain that this process should be used to model and solve the rest of the problems. DIFFERENTIATED INSTRUCTION CLOSING STATEMENT: Struggling learners: Some students may start subtracting Today we used base-ten blocks to subtract the hundreds first, then the tens, then the ones. Remind three-digit numbers. Tomorrow we will draw them to always start with the ones, because later, when models to help us subtract three-digit numbers. they will need to regroup to subtract, they will have toCopyright © by SPOTS Educational Resources. All rights reserved. start with the ones column. 39

Chapter 6 Lesson 10: Drawing to Subtract INTRODUCTORY STATEMENT: II. Drawing to subtract three-digit numbers Yesterday we used base-ten blocks to subtractthree-digit numbers. Today we will make simple math Write 485 – 272 on the board. Say: Sometimes we may not have base-ten blocks available. We can draw simple pictures of the drawings to subtract three-digit numbers. models to help us subtract. How can we show the first number, 485? [Elicit how to make a simple math drawing to show 485.] GOAL: We have 4 hundreds, 8 tens, and 5 ones. Now let’s subtract 272. Which column do we subtract first? [the ones] How many ones Students will draw models to subtract three-digit num- will we subtract? [2] [Cross off two of the five dots.] How many bers. ones are left? [3] [Write 3 in the ones place of the difference.] MATERIALS NEEDED: base-ten blocks (preferably Now let’s subtract the tens. How many tens will we cross off? [7] magnetic foam); blank sheets of paper [Cross off seven of the eight vertical lines.] How many tens are left? [1] [Write 1 in the tens place of the difference.] Finally,Common Core Standards: CCSS2.NBT.7 let’s subtract the hundreds – how many hundreds will we cross off? [2] [Cross off two of the four squares.] How many hundreds LESSON WARM-UP are left? [2] [Write 2 in the hundreds place of the difference.] So, 485 – 272 = 213. Review facts for fluency using the My Math Facts practice sheets. III. Practice THINKING TRIGGER Write 567 – 425 on the board. Ask two volunteers to come up to the board – one to make a simple math drawing for 567, Write 435 – 213 on the board. Ask: If we don’t have base- and the other to solve the problem by crossing off 425 and ten blocks, what can we use to help us subtract? writing the difference. Repeat the process with 692 – 372, using a simple math drawing to show the subtraction.CONCEPT DEVELOPMENT STUDENT TEACHER:I. Reviewing using models to subtract Give each student a blank sheet of paper. Write the equation three-digit numbers 254 – 152 in column form on the board. Ask students to make a simple math drawing to show the subtraction, then writeOn the board write 465 – 312 in a place-value chart labeled H, the difference. Call on a volunteer to copy his or her mathT, O. Say: Let’s use base-ten blocks to find the difference. [Draw drawing on the board. Fill in the difference in the equation.another, larger place-value chart. Elicit how to show the Discuss some mistakes that can be made, such as not liningnumber 465 with base-ten blocks, and place the models in up the columns, not subtracting the ones first, and so on.the chart. Remove blocks as you subtract with the class.] Now Make sure students see the connection between the hands-let’s take away blocks to subtract 312. We start with the ones. We on models, the simple math drawings, and the writtenhave 5 ones, and we take away 2 ones. How many ones are left? algorithm.[3] [Write 3 in the ones place of the difference.] We have 6 tens,and we take away 1 ten. How many tens are left? [5] [Write 5 Copyright © by SPOTS Educational Resources. All rights reserved.in the tens place of the difference.] We have 4 hundreds, andwe take away how many hundreds? [3] How many hundreds areleft? [1] [Write 1 in the hundreds place of the difference.] So,the difference of 465 – 312 is 153.[Erase the numbers, remove the models, and continue to usethe place-value charts as you work through the rest of theproblems in the lesson.]40

Using the Book: pages 61-62 Drawing to Subtract Make a simple math drawing to subtract. Write the difference. Make a simple math drawing to subtract. Write the difference. 1. H T O HT O 1. H T O HTO 37 4 44 5 –2 1 3 –2 0 5 161 240 2. H T O HTO 2. H T O HTO 54 2 28 7 –2 3 0 –2 0 4 312 83 3. H T O HTO Subtract. 4. H T O 5. H TO 3. H T O 46 8 45 3 –2 0 4 36 9 54 6 –2 2 1 –1 4 2 –2 1 1 264 232 227 335 9. 5 Let’s Review! Subtract. 6 12 6. 3 7. 4 8. 7 –28 41 6 5 13 8 10 34 –19 –3 5 –33 27 18 47 Chapter 6 Lesson 10 2.NBT.7 61 62 Now let’s practice subtracting three-digit numbers, using column to show how many tens are left after they regroup, simple math drawings. and they will write a small 1 to the left of the number in the ones column to show that they now have 10 more ones (a For Let’s Review, remind the students that before they teen number). subtract, they will write a small number above the tens DIFFERENTIATED INSTRUCTION CLOSING STATEMENT: Struggling learners: Remind students that only the first Today we made simple math drawings to subtract number in the subtraction problem should be drawn and three-digit numbers. Tomorrow we will subtract that the second number tells how many to cross off; they should not be drawing both numbers. If students are three-digit numbers with regrouping tens. having trouble determining how many of each model toCopyright © by SPOTS Educational Resources. All rights reserved. draw, emphasize that they should rely on the numbers in the place-value chart (rather than on the word form of the number; for example, for the number 243, a 4 in the tens column of the place-value chart should be represented by four lines. This may be easier to understand than inter- preting the number “forty”). 41

Chapter 6 Lesson 11: Three-Digit Subtraction: Regrouping Tens INTRODUCTORY STATEMENT: Let’s cross out the 5 and write a small 4 above it to show that Copyright © by SPOTS Educational Resources. All rights reserved. We’ve learned how to subtract two-digit numbers now there are 4 tens. [Cross out the 5 in the tens column, and with regrouping. Today we will subtract three-digit write a small 4 above it.] How many do we have in the ones column now? [16] So next to the 6 ones we write a 1, for the 1 ten numbers with regrouping tens. that we regrouped, to show the teen number 16. [Write a small 1 to the left of the 6 in the ones column.] GOAL: Since we now have 16 ones, we can take away 7 ones. Students will use models to subtract three-digit num- [Remove 7 cubes.] How many ones are left? [9] [Write 9 in bers, regrouping tens. the ones column of the difference. Continue modeling the MATERIALS NEEDED: base-ten blocks (preferably subtraction: Remove 3 rods from the remaining 4 rods, and 1 magnetic foam for the teacher, and basic base-ten flat from the 3 flats, and fill in the difference in each column models for the students); blank sheets of paper as you go along.] How many hundreds, tens, and ones are left? [2 hundreds, 1 ten, 9 ones] [Point to the models in eachCommon Core Standards: CCSS2.NBT.7 column as the students respond.] So, 356 – 137 = 219. There are 219 bottles left to bring to the recycling center on Tuesday. LESSON WARM-UP [Erase the numbers, remove the models, and continue to use the place-value charts as you work through the rest of the Review facts for fluency using the My Math Facts problems in the lesson.] practice sheets. II. Drawing to subtract three-digit numbers, THINKING TRIGGER regrouping tens On the board write 356 – 4 and 350 – 4. Ask: How are these Say: Now let’s solve another problem, but this time let’s make a problems the same? How are they different? simple math drawing to help us subtract. [Write 453 – 238, and elicit how to make a simple math drawing to show 453.] FirstCONCEPT DEVELOPMENT let’s subtract the ones. Are there enough ones to subtract from? [No; there are only 3 ones.] What can we do? [regroup 1 tenI. Using models to subtract three-digit as 10 ones to make 13 ones.] Let’s show this. We cross out one numbers, regrouping tens ten (one vertical line), and we draw 10 ones (ten dots) next to the three ones. [Circle the ten on the right, and draw an arrowSay: The second-grade class collected 356 plastic bottles to from there to the ones. Draw ten dots to the left of the threerecycle. The class gave 137 bottles in to the recycling center on dots. Then cross out the ten that is circled.] Now let’s showMonday. How many bottles were left to give in on Tuesday? that we regrouped, by marking the subtraction problem. HowAsk: Should we add or subtract to solve the problem? [subtract] many tens are there now? [4] How do we show this? [Cross out[Write 356 – 137 on the board in a place-value chart labeled the 5 in the tens column, and write a small 4 above it.] HowH, T, O.] Let’s use base-ten blocks to help us subtract. [Draw a many ones do we have now in the ones place? [13] So we’ll writelarge place-value chart. Elicit how to show 356 with base-ten in a number 1, next to the 3 ones, to make it 13. [Write a 1 to theblocks, and place the models in the chart.] What do we subtract left of the 3 in the ones column.]first? [the ones] We need to subtract 7 ones. Are there enoughones to subtract from? [No; there are only 6 ones.] What do we Now we can subtract. How many ones do we subtract? [Wedo if we don’t have enough ones to subtract from? [We regroup; subtract 8 ones from 13 ones.] [Cross off eight dots.] Howwe trade 1 ten for 10 ones to form a teen number.] Let’s show many ones are left? [5 ones] [Write 5 in the ones column of thethis: We trade 1 ten (one rod), for 10 ones (ten cubes), and we put difference.] Next we subtract the tens: 4 tens minus 3 tens is…?them in the ones place to form a teen number. [Remove one [1 ten] [Cross off three vertical lines, and write 1 in the tensrod, and place ten cubes in the ones place.] Now let’s show place of the difference.] And last, we subtract the hundreds. 4that we regrouped, by marking the subtraction problem that we hundreds minus 2 hundreds is…? [2 hundreds.] [Cross off twowrote on the board. How many tens do we have now? [4 tens] flats, and write 2 in the hundreds place of the difference.] So, 453 – 238 = 215.42 Repeat as above with 362 – 245, using a math drawing to represent the subtraction process.

Using the Book: pages 63-64 3-Digit Subtraction: Regrouping Tens H TO 1. Subtract the ones. Regroup a ten as 10 ones to form a teen number. Draw the new ones. Write When there are not enough ones the new numbers. Cross off to subtract. Write the difference. 3 to subtract, we regroup a ten as 10 ones to form a teen number. 1. H T O 3 4 16 2 –1 2 9 2. Subtract the tens. 3. Subtract the hundreds. 4 3 16 217 –1 2 8 308 Regroup a ten as 10 ones to form a teen number. Draw the new ones. 2. Write the new numbers. Cross off to subtract. Write the difference. H TO 1. H T O 5 3 3 6 13 4 4 12 – 49 –2 1 9 314 223 Subtract. Regroup if necessary. 2. H T O 5 3. H T O 4. H TO 5. H TO 4 6 14 4 6 7 –1 2 6 4 5 15 9 7 12 6 8 10 338 –2 3 6 –5 2 8 –4 2 3 219 444 25 7 Make a simple drawing to help you subtract. Solve. 6. Jasmine’s book is 342 pages. She has read 126 pages. How many pages does Jasmine have left to read? 3. H T O H TO Jasmine has 216 pages left to read. 4 3 3 5 11 3 4 12 –2 1 4 –1 2 6 137 216 Chapter 6 Lesson 11 2.NBT.7 63 64 Now let’s practice subtracting three-digit numbers. are crossed off [in the annotated answers included for teach- ers’ use] in the way that students learned to subtract from Discuss the demonstration at the top of page 63. Explain teen numbers. As you circulate and observe students’ work, that the exercises that follow are to be solved the same remind them about these strategies, for example, crossing off way as in the demonstration. a large number, such as 8, from the group of 10 new ones.) (Note: As you can see in the student pages above, the onesCopyright © by SPOTS Educational Resources. All rights reserved. STUDENT TEACHER DIFFERENTIATED INSTRUCTION Divide the class into groups of four. Give each group base- Struggling learners: When regrouping a ten, some ten blocks, and then give each group a paper with a different students may forget to deduct 1 ten from the tens col- subtraction equation (that requires regrouping of tens) umn. Instruct them to first deduct 1 from the tens digit, to solve, such as 346 – 139, 562 – 127, 554 –26, and so on. and then add that ten to the ones column (by writing in a Write each equation in a labeled place-value chart. Have the small 1 to the left of the ones digit.) Explain that deduct- students in each group model the problem using base-ten ing from the tens column “allows” them to add the ten to blocks and then fill in the equation on the paper. When they the ones digit. are finished, have groups share their work with the class. Ask questions such as: Did the tens need to be regrouped? Why? Do CLOSING STATEMENT: you always have to regroup tens when subtracting three-digit Today we subtracted three-digit numbers numbers? Why did you write a small 1 in the ones column? with regrouping tens. Tomorrow we will subtract from 100. 43

Chapter 6 Lesson 12: Subtracting from 100 INTRODUCTORY STATEMENT: Erase the numbers, remove the models, and continue to use We’ve learned how to regroup 1 ten when we the place-value charts as you work through the rest of the subtract. Today we will learn how to regroup problems in the lesson. 1 hundred when we subtract. Repeat with 100 – 30. GOAL: II. Drawing to subtract from 100 Students will use models to subtract from 100. Write 100 – 70 on the board. Say: Let’s subtract 70 from 100. MATERIALS NEEDED: base-ten blocks (preferably This time we will make a simple drawing to subtract. [Draw magnetic foam); blank sheets of paper one square in the hundreds column. Point to it and say:] We cannot subtract 7 tens from the hundred. What can we do? [WeCommon Core Standards: CCSS2.NBT.7 can regroup 1 hundred to make 10 tens.] Let’s show this. We cross out the hundred, and we draw 10 tens. [Circle and cross LESSON WARM-UP off the square. Draw an arrow pointing right, and draw ten vertical lines in the tens column.] Now let’s show that we Review facts for fluency using the My Math Facts regrouped, by marking the subtraction problem. How many practice sheets. hundreds are there now? [none] How do we show this? [Cross out the 1 in the hundreds column.] How many tens do we THINKING TRIGGER have now in the tens place? [10] So we’ll write in a number 1, next to the 0 tens, to make it 10 tens. [Write a 1 to the left of the Write 10 – 6, and draw a ten (vertical line) next to it. Ask: 0 in the tens column.] How do we show on a drawing how to regroup 1 ten to help us subtract 10 – 6? Now we can subtract. How many tens do we subtract? [We subtract 7 tens from 10 tens.] [Cross off seven vertical lines.]CONCEPT DEVELOPMENT How many tens are left? [3 tens] [Write 3 in the tens column of the difference.] There are no hundreds to subtract, so,I. U sing models to subtract from 100 100 – 70 = 30.Write 100 – 40 on the board in a place-value chart labeled H, T, Repeat with 100 – 50. Elicit how to make a simple mathO. Draw a larger place-value chart for models, and place one drawing to show the subtraction, and discuss how to recordflat in the hundreds column. Say: First we subtract the ones. the regrouping in the equation.There are no ones, so I will write a 0 in the ones place. [Write 0in the ones place of the difference.] Next we subtract the tens. STUDENT TEACHERHow many tens do we need to subtract? [4] But we have onlyone hundred. Let’s see how we can do this. We need to have tens Write 100 – 20 on the board. Have students draw to show thefrom which to subtract. Let’s regroup 1 hundred to make 10 tens, regrouping and the subtraction. Then have them show thesince 10 tens is the same as 1 hundred. [Remove the flat and regrouping process in the problem written in column formreplace it with ten rods.] Now let’s write how we regrouped the and fill in the difference. Ask: Why do we need to regroup 1001 hundred. How many hundreds are there now? [none] So let’s as 10 tens to solve this problem?cross off the 1. [Cross off the 1 in the hundreds column.] Howmany tens are there now? [10] And let’s write a small 1 next to Copyright © by SPOTS Educational Resources. All rights reserved.the 0 in the tens column, to show that now there are 10 tens inthe tens place. [Write a small 1 to the left of the 0 in the tenscolumn.] Now we can take away 4 tens. [Remove 4 tens.] Howmany tens are left? [6] 10 tens minus 4 tens equals 6 tens; and6 tens is 60. So, 100 – 40 = 60.44

Using the Book: pages 65-66 Subtracting from 100 Fill in the blanks to solve. Regroup 1 hundred as 10 tens. Draw the new tens. Write the new numbers. Cross off to subtract. Write the difference. When we need to subtract tens, and we have only hundreds, 1. 100 – 60 H TO we regroup 1 hundred as 10 tens. 10 tens 10 0 100 – 40 H TO – 6 tens – 60 10 tens – 4 tens 1 10 0 4 tens 40 6 tens – 40 2. 100 – 80 H TO 60 10 tens 10 0 Fill in the blanks to solve. Regroup 1 hundred as 10 tens. Draw the new – 8 tens – 80 tens. Write the new numbers. Cross off to subtract. Write the difference. 2 tens 20 1. 100 – 20 H TO 10 tens 3. 100 – 30 H TO 10 0 10 tens – 2 tens – 20 10 0 8 tens – 3 tens – 30 80 7 tens 70 2. 100 – 50 10 tens H TO Subtract. Regroup if necessary. – 5 tens 10 0 4. H T O 5. H T O 6. H TO 5 tens – 50 10 0 10 0 10 0 50 – 90 – 40 – 10 3. 10 60 90 100 – 70 H TO Let’s Review! Subtract. 10. 6 10 tens – 7 tens 10 0 7. 4 8. 6 9. 8 7 17 – 70 –39 3 tens 5 16 7 14 9 10 30 –2 8 –4 9 –2 4 38 28 25 66 Chapter 6 Lesson 12 2.NBT.5 65 66 Now let’s practice subtracting from 100. tens, you can regroup 1 hundred to make 10 tens, and When you have only hundreds and you need to subtract then subtract. DIFFERENTIATED INSTRUCTION CLOSING STATEMENT: Struggling learners: Point out to students that when Today we subtracted tens from 100. Tomorrow we they added tens numbers to get a sum greater than 100, will subtract three-digit numbers, regrouping tens. they had to group ten of the tens together to make 100Copyright © by SPOTS Educational Resources. All rights reserved. and then add the rest. To subtract, they actually have to do the opposite – take apart the group of 100 and make 10 tens. Using models, demonstrate this difference by bundling and unbundling 10 tens to solve 60 + 80 and 100 – 60. 45

Chapter 6 Lesson 13: Three-Digit Subtraction: Regrouping Hundreds INTRODUCTORY STATEMENT: in the ones place. Let’s subtract the tens. We need to subtract 7 We’ve learned to subtract three-digit numbers with tens. Are there enough tens from which to subtract? [No; there regrouping tens. Today we will subtract three-digit are only 5 tens.] We need to have more tens so that we can subtract. Let’s regroup 1 hundred as 10 tens, and put them in the numbers with regrouping hundreds. tens place. [Remove one flat, and place ten rods in the tens place.] Now let’s show how we regrouped on the subtraction GOAL: problem. How many hundreds do we have now? [3] Let’s cross out the 4 and write a small 3 above it to show that now there Students will use models to subtract three-digit are 3 hundreds. We have 5 tens and another 10 tens. How many numbers, regrouping hundreds. tens do we have in the tens column now? [15] So we write a 1 MATERIALS NEEDED: base-ten blocks (preferably next to the 5 tens to show the number 15. magnetic foam for the teacher and basic base-ten models for the students); blank sheets of paper Now that there are 15 tens, we can take away 7 tens. [Remove seven rods.] How many tens are left? [8] Now let’s subtract theCommon Core Standard: CCSS2.NBT.7 hundreds. 3 hundreds minus 1 hundred equals…? [2 hundreds] [Remove one flat, and fill in 2 in the hundreds column of the LESSON WARM-UP difference.] So, 450 – 170 = 280. Review facts for fluency using the My Math Facts What do we do when there aren’t enough tens from which to practice sheets. subtract? [Regroup 1 hundred as 10 tens, and put those 10 tens in the tens place.]THINKING TRIGGER III. Drawing to subtract three-digit numbers, regrouping hundreds Ask: How will solving 120 – 40 be similar to solving 100 – Say: Now let’s solve another problem, but this time let’s make a Copyright © by SPOTS Educational Resources. All rights reserved. 40? Explain. simple math drawing to help us subtract. [Write 657 – 285, and elicit how to make a simple math drawing to show 657. FillCONCEPT DEVELOPMENT in the equation and draw as you go along.] First let’s subtract the ones. Are there enough ones from which to subtract? [yes]I. Reviewing subtracting from 100 [Cross off 5 ones from the math drawing.] 7 ones minus 5 ones equals…? [2 ones] Now let’s subtract the tens. Are there enoughOn the board write 100 – 80 in a place-value chart labeled tens from which to subtract? [No; there are only 5 tens.] WhatH, T, O, and draw a square (representing hundreds) to the can we do? [Regroup 1 hundred as 10 tens, and put thoseright of the equation. Ask: How can we subtract tens if we have 10 tens with the five tens to make 15 tens.] How manyonly one hundred? [We need to regroup 1 hundred to make hundreds are there now? [5] How do we show this? [Cross out10 tens.] [Elicit how to model the regrouping in the math the 6 in the hundreds column, and write a small 5 above it.]drawing, and discuss how to show the regrouping in the We have 5 tens and another 10 tens. How many tens do we havesubtraction problem. Then erase the numbers, and continue now in the tens place? [15] We write in a number 1 next to the 5to use the place-value chart as you work through the rest of tens to show the number 15.the problems in the lesson.] Now we can subtract. [Cross off 8 lines.] How many tens areII. Using models to subtract three-digit left? [7] 15 tens minus 8 tens equals 7 tens. And last, we subtract numbers, regrouping hundreds the hundreds. 5 hundreds minus 2 hundreds equals…? [3 hundreds.] [Cross off 2 hundreds.] So, 657 – 285 = 372.Write 450 – 170 on the board. Say: Let’s use base-ten blocksto help us subtract. [Draw a large place-value chart for the Repeat with 468 – 175, using simple math drawings tomodels. Elicit how to show 450, and place the models in represent the subtraction process. Be sure to discuss how tothe chart. Fill in the equation as you go along.] What do we show the regrouping in the drawing and in the subtractionsubtract first? [the ones] There are no ones, so I will write a 0 problem.46

Using the Book: pages 67-68 3-Digit Subtraction: Regrouping Hundreds H TO 1. Subtract the ones. Regroup, draw, and cross off to subtract. Write the difference. 2. Subtract the tens. 2 1. H T O When we do not have enough 3 12 7 tens to subtract, we regroup 2 –15 2 1 hundred as 10 tens. 3. Subtract the hundreds. 3 16 7 175 –19 4 173 Regroup, draw, and cross off to subtract. Write the difference. 2. H T O 1. H T O 3 3 4 15 6 4 12 5 –19 2 –16 2 264 26 3 Subtract. Regroup if necessary. 2. H T O 3 3. H T O 4. H T O 5. H TO 4 14 8 3 5 6 –26 3 4 11 5 6 18 9 7 17 5 18 5 –17 1 –29 4 –39 4 3. H T O 244 395 38 1 2 Make a simple drawing to help you subtract. Solve. 3 15 9 –18 3 6. Lynn’s family has to drive 225 miles to visit their family. They have driven 184 miles already. 17 6 How many more miles do they have left to drive? H TO They have 41 miles left to drive. 1 2 12 5 –1 8 4 41 Chapter 6 Lesson 13 2.NBT.2 67 68 Now let’s practice subtracting three-digit numbers. If we for 10 tens, and we add those 10 tens to the number in the don’t have enough tens to subtract, we trade 1 hundred tens column.Copyright © by SPOTS Educational Resources. All rights reserved. STUDENT TEACHER DIFFERENTIATED INSTRUCTION Divide the class into groups of four. Give each group base- Struggling learners: Some students may regroup when ten blocks, and then give each group a different subtraction regrouping is not needed, for example, in the problem equation (that requires regrouping hundreds) to solve, such 368 – 325. Have them use base-ten blocks to show the as 456 – 275, 457 – 281, 245 – 152, and so on. Write each subtraction. Ask: What is the greatest number of ones equation in a labeled place-value chart. Have the students we can subtract from 368 without regrouping? What is in each group model the problem using base-ten blocks the greatest number of tens we can subtract without and then fill in the equation on the paper. When they are regrouping? finished, have groups share their work with the class. Ask questions such as: Which place value needed regrouping? Do CLOSING STATEMENT: you always have to regroup hundreds when subtracting three- Today we subtracted three-digit numbers with digit numbers? Why did you write a small 1 in the tens column? regrouping hundreds. Tomorrow we will subtract three-digit numbers with regrouping both tens and hundreds. 47

Chapter 6 Lesson 14: Three-Digit Subtraction: Regrouping Tens and Hundreds INTRODUCTORY STATEMENT: we have now? [3] We have 4 tens and another 10 tens. How Copyright © by SPOTS Educational Resources. All rights reserved. Yesterday we used models to subtract three-digit many tens do we have now? [14] Now that we have 14 tens, we numbers with regrouping hundreds. Today we will can subtract. [Remove 6 rods.] How many tens are left? [8] 14 use models to subtract three-digit numbers with tens minus 6 tens equals 8 tens. Last, we subtract the hundreds. Let’s subtract 2 hundreds from 3 hundreds. How many hundreds regrouping both tens and hundreds are left? [1] So 453 – 267 = 186. [Erase the numbers and remove the models. Continue to use the place-value chart as you GOAL: work through the rest of the problems in the lesson.] Students will use models to subtract three-digit num- Repeat with 546 – 159. bers, regrouping both tens and hundreds. Materials needed: base-ten blocks (preferably mag- II. Drawing to subtract three-digit numbers, netic foam for the teacher and basic base-ten models regrouping tens and hundreds for the students); blank sheets of paper Write 423 – 335 on the board. Say: We will make a simpleCommon Core Standard: CCSS2.NBT.7 math drawing to subtract. [Elicit how to make a simple math drawing for 423. Fill in the equation and draw as you go LESSON WARM-UP along.] Now, let’s subtract. First we subtract the…? [ones] Are there enough ones from which to subtract 5? [no] What should Review facts for fluency using the My Math Facts we do? [Regroup 1 ten to make 10 ones.] How do we show practice sheets. this? [Cross off 1 ten and draw 10 ones.] How do we show the regrouping on the problem? [Cross out 2 in the tens column THINKING TRIGGER and write a small 1 above it, and write a small 1 in ones column to show 13.] Now we have enough ones from which On the board write 245 – 137 and 245 – 152. Ask: How to subtract. 13 minus 5 equals…? How many ones are left? [8] will we need to regroup to subtract in each of these prob- lems? Explain. Next we subtract the…? [tens] Do we have enough tens from which to subtract 3 tens? [no] What do we do? [RegroupCONCEPT DEVELOPMENT 1 hundred as 10 tens.] How do we show this? [Cross out 1 hundred and draw 10 tens.] How do we show the regroupingI. Using models to subtract three-digit on the problem? [Cross off 4 in the hundreds column and numbers, regrouping tens and hundreds write a small 3 above it, and write a small 1 next to the 1 in the tens column.] We can subtract 3 tens from 11 tens. HowWrite 453 – 267 on the board in a place-value chart labeled many tens are left? [8] Last, we subtract the hundreds. HowH, T, O. Fill in the equation as you go along. Elicit how to many hundreds are left? [none] So, 423 – 335 = 88.model 453, and place the base-ten blocks on the board. Say:What do we subtract first? [the ones] Are there enough ones to Repeat the activity with 560 – 274. Have five volunteerssubtract 7? [no] What do we need to do? [Regroup 1 ten as 10 come up to the board in turn to solve it: one to make a simpleones.] [Have a volunteer come up to the board and exchange math drawing for the minuend (the first number); one toone rod for ten cubes, and place them to the left of the three show regrouping the tens in the drawing; one to show howcubes.] How do we show the regrouping on the problem? [Cross to represent the regrouping of the tens in the equation andout the 5 in the tens place, write a small 4 above it, and write the difference of the ones; one to show regrouping thewrite a small 1 next to the 3 ones to show the number 13.] hundreds in the drawing; and one to show how to representNow we can subtract the 7 ones. [Remove 7 cubes.] How many the regrouping of the hundreds in the equation and writeones are left? [6] Now let’s subtract the tens. Do we have enough the difference of the tens and of the hundreds.tens to subtract 6 tens? [no] What do we need to do? [Regroup1 hundred as 10 tens.] [Have a volunteer exchange one flat When finished, ask: Why do we look at the digits in the onesfor ten rods, and place them to the left of the four rods.] Let’s column first? [to find out if we need to regroup a ten toshow the regrouping on the problem. How many hundreds do make 10 ones before we subtract the tens] Which number changed twice? [the tens digit ] Why? [We regrouped two times: First we regrouped 1 ten as 10 ones, so the 6 tens became 5 tens, then we regrouped 1 hundred as 10 tens, so the 5 tens became 15 tens.]48

Using the Book: pages 69-70 3-Digit Subtraction: Regrouping Tens and Hundreds H TO Sometimes we need to regroup twice. Regroup, draw, and cross off to subtract. Write the difference. 1. Subtract the ones. 1. 2 11 When there are not enough ones to H TO 3 2 15 subtract, we regroup a ten as 10 ones 3 10 –13 7 to form a teen number. 2. Subtract the tens. 4 1 17 18 8 When we do not have enough tens to –28 9 subtract, we regroup 1 hundred as 10 tens. 3. Subtract the hundreds. 12 8 Regroup, draw, and cross off to subtract. Write the difference. 2. H TO 1. 2 13 H TO 2 12 3 4 13 –16 8 3 3 17 –16 8 17 5 16 9 3. H TO 2. 3 14 H TO 3 12 4 5 10 –27 4 4 3 14 –17 7 17 6 25 7 4. H TO Chapter 5 Lesson 14 2.NBT.2 69 2 15 Now let’s practice subtracting three-digit numbers, regroup- 3 6 12 ing tens and hundreds. When there aren’t enough ones from –28 8 which to subtract, we regroup 1 ten as 10 ones and write in a 74 70 1 to make a teen number in the ones column. When there aren’t enough tens from which to subtract, we regroup 1 hundred as 10 tens and write in a 1 to make a teen number in the tens column. STUDENT TEACHER DIFFERENTIATED INSTRUCTION Divide the class into pairs, and distribute base-ten blocks. Struggling learners: Some students may get over- Write 340 – 149 on the board. Have one partner model and whelmed by the process of regrouping twice and may solve with base ten blocks, explaining as he/she goes along. forget some steps. To help keep track of completed steps Have the other partner write the problem on a sheet of paper in the process, direct them to make a checkmark above and explain how to subtract in column form. Then have the the ones column after they are all finished regrouping partners switch roles to solve 413 – 257. tens and subtracting ones. Then have them move on to the tens column, again making a checkmark above theCopyright © by SPOTS Educational Resources. All rights reserved. tens column after they have completed the process of regrouping hundreds and subtracting tens. CLOSING STATEMENT: Today we subtracted three-digit numbers with regrouping tens and hundreds. Tomorrow we will practice subtracting three-digit numbers with regrouping tens and hundreds. 49

Chapter 6 Lesson 15: Three-Digit Subtraction: Regrouping Tens and Hundreds with 0 in the Tens Place INTRODUCTORY STATEMENT: II. Using models to subtract three-digit Copyright © by SPOTS Educational Resources. All rights reserved. Yesterday we used models to subtract three-digit numbers with zero in the tens place numbers, regrouping tens and hundreds. Today we will practice subtracting three-digit numbers, On the board write 502 – 176 in a place-value chart labeled H, T, O. Fill in the equation as you go along. Elicit how to regrouping tens and hundreds when there is a model 502, and place the models on the board. Ask: What do 0 in the tens place. we subtract first? [the ones] [Elicit that there are not enough ones from which to subtract 6.] What do we need to do? GOAL: [regroup a ten as 10 ones] [Point to the 0 in the tens place in 502.] There are no tens to regroup. When there are not enough Students will use models as they practice subtracting tens to regroup, we need two steps: three-digit numbers, regrouping tens and hundreds with 0 in the tens place. Step 1: First we regroup 1 hundred as 10 tens. [Remove one Materials needed: base-ten blocks (preferably magnetic flat, and place ten rods to the right of the flats.] How do we foam for the teacher and basic base-ten models for the show this on the problem? [Cross out the 5 and write a small students); blank sheets of paper 4 above it, and write a 1 next to the 0 in the tens column to show 10 tens.]Common Core Standard: CCSS2.NBT.7 Step 2: Now we have 10 tens, but we still don’t have enough LESSON WARM-UP ones from which to subtract. What can we do? [Elicit that we can regroup one of those tens as 10 ones. Remove one rod Review facts for fluency using the My Math Facts and place ten cubes next to the two cubes.] This leaves us practice sheets. with 9 tens. We add the 10 ones to the 2 ones to make 12. How do we show this in the equation? [Cross out the 10 and write THINKING TRIGGER a small 9 above it, and write a 1 next to the 2 in the ones column.] Now we have enough ones to subtract. [Remove six On the board write 342 – 265, 453 – 228, and 419 – 236. cubes.] How many ones are left? [6] Now we can subtract the Ask: In which problem do we need to regroup only tens? tens. [Remove seven rods.] How many tens are left? [2] And In which problem do we need to regroup only hundreds? last, we subtract the hundreds. [Remove one flat.] How many In which problem do we need to regroup both tens and hundreds are left? [3] So, 502 – 176 = 326. [Erase the numbers. hundreds? Explain how you know. Continue to use the place-value chart as you work through the rest of the problems in the lesson.]CONCEPT DEVELOPMENT III. Drawing to subtract three-digit numbers,I. Subtracting three-digit numbers, with zero in the tens place regrouping tens and hundreds Write 403 – 256 on the board. Say: Now let’s draw base-tenWrite 348 – 129 on the board. Have a volunteer come up to blocks to help us find the difference. [Elicit how to show 403the board and make a simple math drawing to represent 348. with a simple math drawing. Fill in the equation and draw asDiscuss whether there are enough ones or tens from which you go along.] First we subtract the ones. [Elicit that there areto subtract, and if not, what to do. Elicit how to show the not enough ones from which to subtract 6.] What should weregrouping in the math drawing and in the equation. Solve do? [regroup a ten] [Point to the 0 in the tens place in 403.]together with the class. There are no tens to regroup. So we need two steps. What do weRepeat with 538 – 474. Ask: Why are there no hundreds in need to do first? [(Step 1:) Regroup 1 hundred as 10 tens.]the answer? [There were not enough tens from which to How do we show this on the problem? [Cross out the 4 andsubtract 7 tens, so we regrouped 1 hundred as 10 tens. write a small 3 above it, and write a 1 next to the 0.]That left us with 4 hundreds. Then we needed to subtract 4hundreds, so there are no hundreds left.] Now we have 10 tens, but we still don’t have enough ones from which to subtract. What do we need to do next? [(Step 2:) Regroup one of those tens as 10 ones.] 10 ones and 3 ones make 13. How do we show this on the problem? [Cross out the 10 in the tens column and write a small 9 above it, and write a 1 next to the 3 in the ones column.] Now we have enough ones from which to subtract. [Cross out six dots.]50

Using the Book: pages 71-72 3-Digit Subtraction: Regrouping with 0 in the Tens Place H TO Sometimes we need to regroup twice. Regroup, draw, and cross off to subtract. Write the difference. 1. Subtract the ones. 29 1. When there are not enough ones to subtract, H TO 3 10 17 and there are no tens to regroup, we need 39 –16 8 two steps: First, regroup 1 hundred as 10 tens. 4 10 10 139 Then, regroup a ten as 10 ones to –24 2 form a teen number. 2. Subtract the tens. 15 8 3. Subtract the hundreds. first second 2. H TO Regroup, draw and cross off to subtract. Write the difference. 29 1. H T O 29 3 10 14 –15 8 3 10 15 –15 9 14 6 14 6 3. H TO 2. H T O 39 39 4 10 12 4 10 16 –24 3 –12 9 15 9 27 7 Chapter 6 Lesson 15 2.NBT.2 Subtract. Regroup if necessary. 4. 5. H TO 6. H TO H TO 29 59 69 3 10 11 6 10 12 7 10 10 –21 2 –35 9 –22 3 89 24 3 47 7 71 72 Now let’s practice subtracting three-digit numbers, re- Point out that the students should draw and mark the grouping when there is a 0 in the tens place. When there regrouping in the problem as they go along: First regroup are not enough ones from which to subtract, and there the hundred as 10 tens, and mark the problem; then are no tens to regroup, we first regroup 1 hundred as 10 regroup 1 ten as 10 ones, and mark the problem. Circu- tens, and then we regroup one of those tens as 10 ones. late to check that students are drawing and marking the regrouping in the correct order. How many ones are left? [7] Next we subtract the tens. [Cross DIFFERENTIATED INSTRUCTION out five vertical lines.] How many tens are left? [4] And last,Copyright © by SPOTS Educational Resources. All rights reserved. we subtract the hundreds. [Cross out two squares.] How many Struggling learners: Distribute base-ten models. Give hundreds are left? [1] So, 403 – 256 = 147. students several problems that have a zero in the tens To summarize, ask: What do we do when we need to regroup 1 place of the minuend and that require regrouping, such ten as 10 ones in order to subtract the ones, but there are 0 tens? as 603 – 445. Have them practice only the regrouping, [First we regroup 1 hundred as 10 tens, then we regroup without solving or marking the regrouping in the equa- one of those tens as 10 ones.] tions, working only with the models, so that they will become familiar with the process of regrouping, and they STUDENT TEACHER will see that after regrouping, there are enough tens and ones from which to subtract. Write 307 – 149 in column form on the board. Distribute base-ten blocks. Have the students solve the problem using CLOSING STATEMENT: models. Ask a volunteer to go to the board and explain the steps he or she used to find the difference. Today we practiced subtracting three-digit numbers in problems where there were not enough ones to subtract and there were no tens to regroup. Tomorrow we will have more practice 51 subtracting three-digit numbers.

Chapter 6 Lesson 16: Three-Digit Subtraction INTRODUCTORY STATEMENT: Solve together with the class (211). Point out that when Copyright © by SPOTS Educational Resources. All rights reserved. We’ve learned to subtract three-digit numbers with there are 0 ones in the number, we can regroup one of theregrouping tens and hundreds. Today we will practice tens to get 10 ones. We write in a 1 next to the 0 to show the all types of subtraction with three-digit numbers. number 10. GOAL: Write 628 – 147 on the board, and repeat as above. Solve together with the class (481). Students will use models as they practice subtracting three-digit numbers, regrouping when necessary. III. Subtracting three-digit numbers, Materials needed: base-ten blocks regrouping hundredsCommon Core Standard: CCSS2.NBT.7 Write 608 – 474 on the board. Use models to represent 608. Discuss whether there are enough ones or tens from which LESSON WARM-UP to subtract, and if not, what to do. Have a volunteer come up to the board and show the regrouping with the models and Review facts for fluency using the My Math Facts in the equation. Point out that when there are 0 tens in the practice sheets. number, we can regroup one of the hundreds. Then we have 5 hundreds and 10 tens, which is the same as 6 hundreds. We THINKING TRIGGER cross off the 6 and write 5 above it, and we write in a 1 next to the 0 to show the number 10. Solve together with the class On the board write 305 – 248, 453 – 112, and 517 – 236 (134). in column form. Ask: In which problems do we need to regroup? In which problems do we not need to regroup? IV. Subtracting three-digit numbers, regrouping both tens and hundredsCONCEPT DEVELOPMENTI. Subtracting three-digit numbers with Write 417 – 248 on the board. Make a simple math drawing to represent 417, and draw and fill in the equation as you no regrouping go along. Discuss whether there are enough ones or tens from which to subtract, and if not, what to do. Point out thatOn the board write 577 – 275 in a place-value chart labeled after we regroup the tens, we have 0 tens, so we will need toH, T, O. Elicit how to make a simple math drawing, and solve regroup the hundreds. Then we will have 3 hundreds and 10together with the class (302). Ask: Why didn’t we regroup to tens (which is the same as the 4 hundreds). Cross off the 4subtract? [We had enough ones and tens from which to and write 3 above it, and write in a 1 next to the 0 to show thesubtract.] [Erase the numbers, and continue to use the place- number 10. Solve together with the class (169).value chart as you work through the rest of the problems inthe lesson.] V. Subtracting three-digit numbers, regrouping with zero in the tens placeII. Subtracting three-digit numbers, regrouping tens Write 301 – 235 on the board. Make a simple math drawing to represent 301. Draw and fill in the equation as you go along.Write 340 – 129 on the board, and fill in the equation as you Discuss whether there are enough ones or tens from whichgo along. Have a volunteer come up to the board and model to subtract, and if not, what to do. Say: This problem has a340. Discuss whether there are enough ones or tens from zero in the tens place. What are the two steps that we need towhich to subtract, and if not, what to do. Elicit how to show do so that there are enough ones from which to subtract? [Firstthe regrouping, both using the models and in the equation. regroup one hundred as 10 tens, then regroup one of the tens as ten ones.] [Solve together with the class (66).] Repeat with 400 – 135. Have the class guide you as you regroup first hundreds and then tens to subtract. Solve together with the class (265).52

Using the Book: pages 73-74 Practice: 3-Digit Subtraction Regroup, draw, and cross off to subtract. Write the difference. Regroup, draw, and cross off to subtract. Write the difference. 1. H T O 1. 2 13 H TO 3 4 10 45 6 –24 7 –23 2 93 22 4 2. 2. H TO H TO 49 6 5 10 10 –24 2 3 7 14 –13 6 25 8 23 8 Make a simple drawing to help you subtract. Solve. 3. 3. Mr. Cooper received 304 orders last week. He shipped 168 of the H TO orders. How many orders does Mr. Cooper still need to ship? 2 11 H TO Mr. Cooper needs to ship 136 more orders. 29 3 2 12 –17 9 3 10 14 –1 6 8 14 3 13 6 4. 2.NBT.7 73 LET’S WRITE! H TO 39 How did you solve exercise 3? I_r_e_g_r_o_u_p_e_d__1_h_u_n_d_r_e_d__a_s_1_0_t_e_n_s_, _a_n_d_I_h_a_d__2_h_u__n_d_re_d__s_le_f_t._T_h_e_n__I__ 4 10 16 r_e_g_r_o_u_p_e_d__1_t_e_n_a_s_1__0_o_n_e_s_t_o__g_e_t _9_t_e_n_s_a_n_d__1_4_o_n__e_s._I_s_u_b_t_ra_c_t_e_d___ – 69 t_h_e__o_n_e_s_: 1_4__–_8__=_6_._I_s_u_b_t_r_ac_t_e_d__th_e__te_n__s:_9__–_6__=_3_._______________ I_s_u_b_t_r_a_c_te_d__th__e_h_u_n_d_r_e_d_s_:_2_–__1_=__1_. _Th__e_d_i_ff_e_re_n__ce__is_1__3_6_. _________ 33 7 74 Chapter 6 Lesson 16 Now let’s practice subtracting three-digit numbers, with After completing Let’s Write!, have several volunteers read and without regrouping. their written explanations and discuss whether they have included all the steps needed to find the difference.Copyright © by SPOTS Educational Resources. All rights reserved. STUDENT TEACHER DIFFERENTIATED INSTRUCTION On the board write 385 – 175, 385 – 179, and 385 – 189 in Struggling learners: Distribute base-ten models. Give column form. Have the students work in pairs to rewrite and students several problems that have a zero in the tens solve the three problems. As students are working, circulate place of the minuend and that require regrouping, such as and ask: For each equation, do we need to regroup tens, ones, 502 – 138. Have them practice regrouping using models both, or neither? [Review students’ work as a class. Ask:] The and recording the process on the equation, without minuend (the first number in the subtraction problem) has solving the equations, so that they will become familiar the same number of tens in all three problems. Do all three with the process of recording the regrouping, and they solutions have the same number of tens? Explain. will see that after regrouping, there are enough tens and ones from which to subtract. CLOSING STATEMENT: Today we reviewed subtracting three-digit numbers, with and without regrouping. Tomorrow we will review what we’ve learned in Chapter 6. 53

Chapter 6 Lesson 17: End-of-Chapter Review INTRODUCTORY STATEMENT: show the regrouping on the equation, and fill it in as you go Yesterday we practiced subtracting three-digit num- along. Solve together with the class (715). bers, with and without regrouping. Today we will IV. Adding three-digit numbers, regrouping review what we’ve learned in Chapter 6. both tens and ones GOAL: Write 246 + 165 on the board. Elicit how to make a simple math drawing to represent the addends. Discuss whether Students will review and practice skills they have you need to regroup the ones or tens, and why. Elicit how to learned in Chapter 6. show the regrouping on the drawing and on the equation. Materials needed: base-ten blocks Draw and fill in the equation as you go along. Solve together with the class (411).Common Core Standards: CCSS2.NBT.7 V. Adding four two-digit addends LESSON WARM-UP Write 65 + 47 + 41 + 39 = ___ in horizontal form on the board. Review facts for fluency using the My Math Facts Elicit which two addends to add together first, and why (41 practice sheets. + 39, because the ones in these numbers add up to 10). Write the addition problem, and find the sum (80). Elicit that THINKING TRIGGER there are two ways to continue: We can continue by adding on the third addend to the sum of the first two (80 + 65 = How do place-value charts help you add or subtract? 145), and then adding the fourth addend to the sum of the first three addends (145 + 47 = 192); or by adding the otherCONCEPT DEVELOPMENT two addends (65 + 47 = 112), and afterward adding the two sums together (112 + 80 = 192). Solve the equation both ways, together with the class.I. Adding three-digit numbers with VI. Subtracting three-digit numbers, Copyright © by SPOTS Educational Resources. All rights reserved. no regrouping regrouping both tens and hundredsOn the board write 245 + 213 in a place-value chart labeled Write 347 – 169 in column form on the board. Make a simpleH, T, O. Find the sum together with the class (458). Ask: Why math drawing to represent 347. Discuss whether there aredon’t we need to regroup in this problem? [When we add the enough ones or tens from which to subtract, and if not, whatones, we have fewer than 10 ones, and when we add the to do. Elicit how to show the regrouping on the drawingtens, we have fewer than 10 tens.] and on the equation. Draw and fill in the equation as you go along. Solve together with the class (178).Erase the numbers, and continue to use the place-value chartas you work through the rest of the problems in the lesson. VII. Subtracting three-digit numbers, regrouping with zero in the tens placeII. A dding three-digit numbers, regrouping ones Write 401 – 238 on the board. Make a simple math drawing to represent 401. Discuss how to regroup a ten when there areWrite 346 + 137 on the board. Discuss whether you need to zero tens. Elicit how to show the regrouping on the drawingregroup the ones or tens, and why or why not. Elicit how to and on the equation. Draw and fill in the equation as you goshow the regrouping on the equation, and fill it in as you go along. Solve together with the class (163).along. Solve together with the class (483).III. Adding three-digit numbers, regrouping tensWrite 430 + 285 on the board. Discuss whether you need toregroup the ones or tens, and why or why not. Elicit how to54

Using the Book: pages 75-76 End-of-Chapter Review Subtract. Regroup, if necessary. You can use the models to help. Add. Regroup if necessary. You can use the models to help. 1. H T O 1. H T O 4 1 3 5 10 23 8 –12 6 +22 7 22 4 465 Add. Regroup if necessary. 2. H T O 2. H T O 3. H TO 4. H T O 3 1 11 1 4 14 1 –27 0 26 4 45 7 32 6 + 15 3 + 45 7 +15 4 17 1 41 7 91 4 48 0 Subtract. Regroup, if necessary. First find the sum of two addends. Add the rest. You can add in any order. 3. H T O 4. H T O 5. H T O 5. Answers will vary. H TO H TO H TO 8 86 7 59 63 + 54 + 38 + 47 11 11 –52 3 11 0 9 9 13 6 10 15 63 + 54 16 4 –48 5 34 4 – 87 + 38 16 4 50 8 51 8 20 2 + 47 Make a simple drawing to help you subtract. Solve. 11 0 6. Mr. Baylor is mailing invitations to all his friends. He wants to send 250 invitations. He’s already mailed out 180 invitations. How many LET’S WRITE! invitations does Mr. Baylor still have to send? How many ones are in the answer to exercise 4? Explain why. H TO N__o_n_e_. _6_+__4_=__1_0_, _s_o_w__e_r_e_g_ro_u__p_1_0__a_s _1_t_e_n_a_n_d__0_o__n_e_s.____________ _________________________________________________________ 1 _________________________________________________________ _________________________________________________________ 2 15 0 Mr. Baylor has to send _7__0_ more invitations. –1 8 0 70 Chapter 6 Lesson 17 75 76 Now let’s practice adding and subtracting three-digit Point out to the students that on the first page of the review numbers. they will add three-digit numbers, and on the second page they will subtract. Remind them to always look at the operation sign before beginning to solve a problem.Copyright © by SPOTS Educational Resources. All rights reserved. STUDENT TEACHER CLOSING STATEMENT: Choose a skill that was taught in this chapter that needs Today we reviewed adding and subtracting more review. Write some examples on the board that require three-digit numbers. Tomorrow we will review that skill, and ask volunteers to come up to the board in turn to solve the examples and to explain how they solved them. skills we’ve learned so far this year. DIFFERENTIATED INSTRUCTION Struggling learners: Some students may regroup when subtracting, even when regrouping is not necessary. Remediate this issue by having students use models or drawings and ask themselves: Are there enough ones/tens to take away? If not—regroup. 55

Chapter 6 Lesson 18: Cumulative Review INTRODUCTORY STATEMENT: Write 66 + 34, and draw an open number line next to it. Solve Copyright © by SPOTS Educational Resources. All rights reserved. Yesterday we reviewed Chapter 6. Today we will re- together with the class. Discuss making two jumps, and that view some of the skills we’ve learned so far this year. the sum of the ones is 10, so we get to 100. GOAL: III. Using the number line to subtract Students will review and practice skills they have learned On the board write 70 – 4 and 83 – 5. Draw an open number since the beginning of the year. line next to each equation. Point out that since 70 is a tens MATERIALS NEEDED: Model coins; index cards, each number, we can make one jump back into the previous ten. with either a two-digit addition problem or a two-digit- Discuss that the difference will be in the 60s, since that is the subtraction problem previous ten. Solve on the number line (66).Common Core Standards: CCSS2.NBT.4; CCSS2.NBT.5; Point to 83 – 5. Discuss that since we are subtracting from aCCSS2.NBT.6; CCSS2.NBT.7; CCSS2.NBT.8; CCSS2.MD.6; two-digit number (83), and we need to subtract more thanCCSS2.MD.8 the 3 ones that there are in 83, we first need to jump back to get to the tens number, and then we need to jump back LESSON WARM-UP for the rest of the ones that we are subtracting. Solve on the number line, jumping back 3 to get to 80, and then jumping Review facts for fluency using the My Math Facts back the rest of the ones that we are subtracting (another 2) practice sheets. to get to the difference (78).] THINKING TRIGGER IV. Writing a number in expanded form Why do you think it’s important to review what we’ve Display four flats, six rods, and three cubes. On the board, learned so far this year in math? write 463 = __________. Review that to write a number in expanded form, we need to write the full value of theCONCEPT DEVELOPMENT hundreds plus the tens plus the ones. Write 463 in expandedI. Finding the value of coins by counting on form (400 + 60 + 3).Review the name and value of each coin. Display three flats and one cube. On the board, write 301On the board, place two quarters, two dimes, three nickels, = __________. Discuss that there are zero tens, so we don’tand three pennies, lined up in a row. Review that we arrange need to write a number of tens. Write 301 in expanded formcoins in order from the greatest value to the least value. Count (300 + 1).the value of the coins together with the class (88 cents). V. Comparing two 3-digit numbersII. Using the number line to add Review the greater than and less than symbols, remindingWrite 58 + 7 on the board. Draw an open number line, and fill students that Al the Alligator always eats (i.e., points to) theit in as you go along. Review how to show the equation on greater number. Review that first we compare the digits inthe number line. Discuss making two jumps: first a jump of the hundreds place; if they are the same, we compare the+2 to get to the next ten (60), then another jump of +5 to get digits in the tens place; and if they are the same, we compareto the sum (65). the ones.Write two equations on the board: 66 + 30 and 66 + 32. Beloweach equation draw an open number line. Review how to VI. Finding the number before and aftershow the equations on the number lines: what number tobegin with (66), and how many to jump (one jump of +30 Point to a number on the number chart. Locate the numberfor the first equation; two jumps, one of +30 and one of +2, before and after it. List the three numbers, and point out thatfor the second equation). the ones digit changes to get to one more and one less.56 VII. Skip-counting by hundreds, tens, and fives On the board write 168, and skip-count by hundreds, starting from 168. Discuss which digits stay the same and which digit changes.

Using the Book: pages 37-38 Complete the number line. Fill in the sum. Cumulative Review Write the number in expanded form. 1. 57 + 40 = 97 40 97 1. 485 = 400 + 80 + 5 2. 709 = 700 + 9 57 +2 Compare. Write >, <, or =. 2. 68 + 32 =100 +32 98 100 3. 4. 5. 903 < 906 30 769 < 804 431 > 429 68 3. 38 + 33 = 71 +33 Write the numbers that come just before and after. 30 +2 +1 6. 7. 8. 38 68 70 71 509 , 510, 511 489 , 490, 491 799 , 800, 801 Complete the number line. Write the difference. –5 Write the number that is 100 more and 100 less. 9. 10. 11. 4. 53 – 5 = 48 3 628 , 728, 828 93 , 193, 293 702 , 802, 902 –2 53 Write the number that is 10 more and 10 less. 48 50 12. 13. 5. 20 – 4 = 16 4 184 , 194, 204 292 , 302, 312 14 . 16 20 709 , 719, 729 Write a number sentence and solve. Use a for the unknown number. Count by fives. Fill in the numbers. 15. 485,490,495, 500 , 505 , 510 6. Jeremy has 60¢. He buys a Step 1. Write the amount of money. Show the amount in a different way. snack for 20¢. Write the number sentence. 16. Later, his mother gives him a quarter as a prize. 60¢ – 20¢ + 25¢ = 65¢ qdd d Answers will vary. How much money does Step 2. Jeremy have now? Solve. 60¢ 40¢ – 20¢ + 25¢ dnp 71 ¢ Jeremy has _6__5_¢ now. 40¢ 65¢ Chapter 6 Lesson 18 77 78 Now let’s practice some skills we’ve learned so far this year. Read the story problem together with students. Elicit from students in which part of the story addition takes place and For each section, read the directions, and have the stu- in which part subtraction takes place. Remind them that dents complete it on their own, while you offer help as both steps need to be shown and completed in order to needed. Review each section together. solve the problem.Copyright © by SPOTS Educational Resources. All rights reserved. Write 254, and skip-count by tens, starting from 254. Discuss DIFFERENTIATED INSTRUCTION which digits stay the same and which digit changes. Also discuss what happens when the number has 9 tens. Struggling learners: Some students may still have diffi- culty with a skill or skills taught so far this year. Have them Write 375, and skip-count by fives, starting from 375. Discuss partner with students who understand the skill(s) and the pattern of the ending numbers (zero and five). Also work through a few exercises together. discuss what happens when the number ends in 95. CLOSING STATEMENT: STUDENT TEACHER Today we reviewed some of the skills we’ve learned so far this year. Tomorrow we will begin Chapter 7! Prepare two types of index cards (one problem per card): 1) two-digit addition (with sums up to 100) that can be solved on the number line, and 2) two-digit subtraction that can be solved on the number line. Divide the class into pairs. Give each pair a set of two index cards, and have the partners work together to solve the problems on the cards. Then have some students share their work with the class. 57