Active Maths CB G3 Inside_LR

2  Dividing Tens and Ones 2.1  Dividing tens by 2 a) Divide 40 by 2. 10 10 10 10 10 10 10 10 40 ÷ 2 = 20 SCHOLASTICb) Divide 30 by 2.10 1 1 1 1 1 10 1 1 1 1 1 10 1 1 1 1 1 10 1 1 1 1 1 10 10 10 1 Divide the tens 2 Regroup the remaining 3 Divide the ones by 2. ten into ones. by 2. 1 1 15 2 30 2 30 2 30 2 ← 2 × 1 ten = 2 tens 2 2 1 ← remainder 1 ten 1 0 ← 1 ten 0 ones 10 10 = 10 ones 0 ← 2 × 5 ones = 10 ones 30 ÷ 2 = 15 Exercise 3 1. Divide. Fill in the missing numbers. 50 ÷ 2 10 10 10 2 50 10 10 10 10 1 1 1 1 1 10 10 1 1 1 1 1 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 55

2. Divide. b) 90 ÷ 2 = a) 60 ÷ 2 = 2.2  Dividing 2-digit numbers Divide 82 by 3. 82 = 8 tens 2 ones 10 10 10 10 1 1 Divide the tens by 3. 10 10 10 10 1 2 3 82 6 ← 3 × 2 tens = 6 tens 2 ← remainder 2 tens SCHOLASTIC 10 10 10 1111 2 Regroup the remaining 10 10 10 1111 tens into ones. 1111 1111 2 1111 3 82 11 6 2 2 ← 2 tens 2 ones = 22 ones 111 111 3 Divide the ones by 3. 10 10 27 111 111 3 82 10 10 6 22 1 1 2 1 ← 3 × 7 ones = 21 ones 1 ← remainder 1 one 111 1 10 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 111 10 1 82 ÷ 3 = 27 R1 56

Exercise 4 b) 87 ÷ 7 Start by dividing the tens. 7 87 1. Divide. a) 64 ÷ 2 d) 77 ÷ 5 2 64 5 77 c) 59 ÷ 3 3 59 SCHOLASTICPractice 2 b) 70 ÷ 2 = 1. Divide. b) 76 ÷ 6 = c) 90 ÷ 5 = a) 80 ÷ 2 = e) 69 ÷ 3 = f) 94 ÷ 9 = h) 89 ÷ 8 = i) 98 ÷ 5 = 2. Divide. a) 41 ÷ 3 = d) 53 ÷ 4 = g) 78 ÷ 7 = I know how to divide 2-digit numbers by 1-digit numbers divide tens by 2 3  Dividing Hundreds, Tens and Ones 3.1  Dividing hundreds and tens by 2 a) Divide 300 by 2. 100 100 10 10 10 10 10 100 10 10 10 10 10 100 100 10 10 10 10 10 100 10 10 10 10 10 100 2 hundreds 10 tens 3 hundreds 300 ÷ 2 = 150 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 57

b) Divide 250 by 2. 100 10 10 100 10 10 1 1 1 1 1 10 100 10 10 1 1 1 1 1 100 10 10 10 100 10 10 100 10 10 1 Divide the hundreds 2 Divide the tens 3 Divide the ones by 2. by 2. by 2. 1 12 125 2 250 2 ← 2 × 1 hundred = 2 hundreds 250 ÷ 2 = 125 SCHOLASTIC 2 250 2 250 22 5 5 4 ← 2 × 2 tens = 4 tens 4 1 ten 0 ones 1 ← remainder 1 ten 1 0 ← = 10 ones 1 0 ← 2 × 5 ones 0 = 10 ones Exercise 5 2 490 1. Divide. Fill in the missing numbers. 490 ÷ 2 = 100 100 10 10 10 10 10 100 100 10 10 10 10 100 100 10 10 10 10 1 1 1 1 1 100 100 10 10 10 10 1 1 1 1 1 2. Divide. b) 520 ÷ 2 = a) 800 ÷ 2 = 58 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

3.2  Dividing 3-digit numbers Divide 451 by 4. 451 = 4 hundreds 5 tens 1 one 100 100 10 10 10 1 1 Divide the hundreds by 4. 100 100 10 10 1 4 451 4 ← 4 × 1 hundred = 4 hundreds SCHOLASTIC 100 100 100 100 10 1 2 Divide the tens by 4. 10 10 10 10 11 4 451 4 5 4 ← 4 × 1 ten = 4 tens 1 ← remainder 1 ten 100 100 100 100 1 1 1 3 Regroup the remaining tens into ones. 10 10 10 10 1 1 1 11 111 4 451 4 11 5 4 1 1← 1 ten 1 one = 11 ones 100 1 100 1 1 4 Divide the ones by 4. 10 1 10 1 1 1 112 100 1 100 1 4 451 10 1 10 1 4 451 ÷ 4 = 112 R3 5 4 11 8 ← 4 × 2 ones = 8 ones 3 ← remainder 3 ones © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 59

Exercise 6 1. Divide. Start by dividing the a) 3 3 7 2 b) 2 4 2 9 hundreds. Regroup if necessary. c) 4 2 5 8 d) 6 1 6 5 Practice 3 1. Divide. SCHOLASTIC a) 100 ÷ 2 = b) 600 ÷ 2 = c) 700 ÷ 2 = d) 950 ÷ 2 = e) 540 ÷ 2 = f) 650 ÷ 2 = 2. Divide. b) 179 ÷ 7 = a) 405 ÷ 5 = c) 120 ÷ 8 = d) 954 ÷ 9 = e) 736 ÷ 3 = f) 384 ÷ 4 = g) 837 ÷ 6 = h) 726 ÷ 5 = I know how to divide 3-digit numbers by 1-digit numbers d ivide hundreds and tens by 2 4  Division by 10 4.1  Dividing numbers by 10 a) 10 1 b) 100 ÷ 10 10 1 10 ÷ 10 100 10 10 10 1 100 30 ÷ 10 = 3 300 ÷ 10 = 30 ÷ 10 1 ÷ 10 10 10 100 60 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

c) 10 1 1 10 1 100 10 1 ÷ 10 10 100 10 100 321 ÷ 10 = 32 R1 When we divide a number by 10, we can get the quotient by removing the digit from the ones place. The digit removed is the remainder. SCHOLASTIC Exercise 7 1. Divide. R b) 900 ÷ 10 = R a) 90 ÷ 10 = c) 92 ÷ 10 = R d) 967 ÷ 10 = R To get the quotient, remove the digit from the ones place. Write the digit in the ones place as the remainder. Mira made some sandwiches and packed them into boxes. Each box had 10 sandwiches. No sandwiches were left. How many sandwiches did Mira make? a) 52 b) 68 c) 79 d) 50 Practice 4 1. Divide. Write the quotient and remainder. a) 600 ÷ 10 b) 58 ÷ 10 c) 106 ÷ 10 quotient = quotient = quotient = remainder = remainder = remainder = d) 730 ÷ 10 e) 161 ÷ 10 f) 502 ÷ 10 quotient = quotient = quotient = remainder = remainder = remainder = I know how to divide 2-digit and 3-digit numbers by 10 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 61

5  Word Problems A shopkeeper had 528 kilograms of rice. After selling 150 k­ ilograms, he packed the remaining rice into sacks of 5 k­ ilograms each. How many sacks of rice were there? How much rice was left? 1 Understand There were 528 kilograms of rice. 150 k­ ilograms the problem. of it were sold. The remaining rice was packed into sacks of 5 k­ ilograms each. I need to find the ­number of sacks of rice to be packed. SCHOLASTIC 2 Plan Draw bar models to solve the problem. what to do. 3 Work out the 528 kg Answer. ? 150 kg 528 kg – 150 kg = 378 kg The shopkeeper had 378 kilograms of rice left after selling 150 kilograms of it. 378 kg 75 5 kg 5 kg 5 378 35 ?? 28 25 378 kg ÷ 5 kg = 75 R3 3 There were 75 sacks of rice. 3 kilograms of rice was left. 4 Check 75 × 5 kg = 375 kg if your answer 375 kg + 3 kg = 378 kg is correct. My answer is correct. 1 . Understand 2 . Plan 3 . Answer 4 . Check 62 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

Exercise 8 Solve the word problems. Draw bar models to help you. 1 . Understand 2 . Plan 3 . Answer 4 . Check 1. Maya had 96 beads. She used all the beads to make 8 bracelets. Each bracelet had the same number of beads. How many beads did she use for each bracelet? 2. Elvin travelled a total distance of 804 kilometres during his 6-day road trip. He travelled the same distance each day. How far did he travel each day? 3. Abdul has 534 oranges. He puts them into boxes of 6. He sells 34 of the boxes. How many boxes of oranges are left? 4. Mrs Arora made 360 sandwiches. She gave 16 sandwiches to her children and packed the rest into boxes of 8. How many boxes of sandwiches did she get? 5. There were 538 rubber bands in a box. The shopkeeper used 16 of them and packed the remaining rubber bands equally into 5 packets. a) How many rubber bands are there in each packet? b) How many rubber bands are left? SCHOLASTIC I know how to: s olve up to 2-step word problems involving division Chapter Review 1. Divide the numbers by 10. Then, match the numbers with the quotient and remainder. 167     67      607     670     671 67 R0   60 R7      67 R1     6 R7    16 R7 63 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

2. Divide. b) 50 ÷ 2 c) 60 ÷ 3 d) 68 ÷ 6 a) 20 ÷ 2 f) 800 ÷ 2 g) 760 ÷ 2 h) 500 ÷ 5 e) 98 ÷ 9 j) 674 ÷ 7 k) 875 ÷ 9 l) 679 ÷ 8 i) 897 ÷ 8 3. Ritu had ` 292. After paying for 3 kilograms of apples, she had ` 40 left. Find the cost of 1 kilogram of apples. 4. There are 120 guests at a wedding. 8 of them are dancing. The remaining guests are sitting at tables with 4 chairs each. How many tables are occupied at the wedding? 5. Mary needs to bake 108 biscuits. She bakes the biscuits in batches of 6. It takes 8 minutes to bake a batch of biscuits. How much time will Mary take to bake all the biscuits? 6. Change the following word problem to a division word problem so that the answer is 5 octopuses. Then, solve the word problem. An octopus has 8 legs. How many legs will 5 octopuses together have? 7. Divya has a 100-rupee note. She buys 2 pens, 2 erasers and a pencil. She has no money left. The pencil and erasers cost ` 34. How much did each pen cost? SCHOLASTIC Maths Lab Activity Dividing numbers by 10 Take number cards (1 to 9). 280 Pick 3 number cards. Form a 2-or 3-digit number using the cards. Write the number formed on a sheet of paper. Divide the number formed by 10. Write the quotient and the remainder. For example, number formed = 208 208 ÷ 10 = 20 R8 64 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

TO 5 Mental Strategies Let’s Revise b) 59 + 7 = d) 63 + 24 = 1. Add mentally. a) 48 + 5 = c) 47 + 32 = 2. Subtract mentally. a) 53 – 7 = c) 29 – 16 = SCHOLASTIC b) 81 – 8 = d) 67 – 23 = 1 Addition 1.1 Adding numbers using the ‘add the tens, then add the ones’ strategy Find the sum of 37 and 58. 10 1 1 10 1 1 37 + 58 10 1 1 10 10 1 1 1 50 8 10 1 1 1 10 10 1 1 1 37 + 58 is the same as 37 + 50 + 8. 37 58 1 Add the tens to the first number. 10 1 1 10 11 37 + 50 87 10 1 1 10 10 1 1 1 2 Add the ones to the result. 10 1 1 1 10 10 1 1 1 87 + 8 95 87 8 37 + 58 = 95 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 65

Exercise 1 1. Write the missing numbers. a)   41 + 10 +7 +3 41 + 17 = b) 38 + 20 38 + 23 = SCHOLASTIC1.2 Adding numbers by making tens Add 54 and 17. 54 + 17 54 is close to 60. 6 can be 6 11 added to 54 to make 60. So, 54 + 17 is the same as 54 + 6 + 11. 1 Make tens. Add 6 to 54. 2 Add 11 to the result. 60 + 11 71 54 + 6 60 54 + 17 = 71 Exercise 2 1. Write the missing numbers. b) 91 + 97 a) 46 + 28 43 = 46 + 4 + = + 3 + 97 = 50 + = + 100 = = 66 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

Practice 1 b) 39 + 44 = c) 57 + 25 = e) 82 + 29 = f) 95 + 36 = 1. Add mentally. h) 58 + 17 = i) 64 + 26 = a) 23 + 18 = k) 76 + 95 = l) 92 + 96 = d) 16 + 78 = g) 33 + 29 = j) 49 + 75 = I know how to add two 2-digit numbers with regrouping mentally SCHOLASTIC 2 Subtraction 2.1 Subtracting numbers using the ‘subtract the tens, then subtract the ones’ strategy Find the difference between 63 and 24. Tens Ones 63 – 24 20 4 63 – 24 is the same as 63 – 20 – 4. Tens Ones 1 Subtract the tens from the first number. 63 – 20 43 2 Subtract the ones from the result. 43 – 4 39 63 – 24 = 39 Exercise 3 1. Write the missing numbers. a)  53 – 10 –4 53 – 14 = b)  62 – 20 – 5 62 – 25 = © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 67

2.2  Subtracting from tens Subtract 19 from 80. 80 – 19 19 is close to 20. Subtracting 19 from 20 is 60 20 easier than subtracting 19 from 80. So, 80 – 19 is the same as 60 + 20 – 19. 1 Subtract 19 from 20. 2 Add 60 to the result. 20 – 19 1 1 + 60 61 SCHOLASTIC 80 – 19 = 61 Exercise 4 1. Write the missing numbers. b) 80 – 59 a) 30 – 16 10 20 60 60 – 59 = 20 – 16 = 80 – 59 = 30 – 16 = 10 + = + = Practice 2 1. Subtract mentally. a) 45 – 19 = b) 63 – 28 = c) 32 – 16 = f) 63 – 55 = d) 54 – 26 = e) 82 – 47 = c) 80 – 36 = 2. Subtract mentally. f) 90 – 39 = a) 50 – 24 = b) 70 – 17 = d) 30 – 18 = e) 40 – 29 = I know how to subtract a 2-digit number from tens subtract a 2-digit number from another © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 2-digit number with regrouping mentally 68

3 Multiplication 7 × 3 = 21 3.1  Multiplying tens or hundreds a) Multiply 7 by 3. 1111111 1 1 1 1 1 1 1 1111111 SCHOLASTIC b) Multiply 70 by 3. 70 × 3 = 7 tens × 3 10 10 10 10 10 10 10 = 21 tens 10 10 10 10 10 10 10 10 10 10 10 10 10 10 = 210 c) Multiply 700 by 3. 700 × 3 = 7 hundreds × 3 100 100 100 100 100 100 100  = 21 hundreds 100 100 100 100 100 100 100 100 100 100 100 100 100 100  = 2100 When multiplying a number ending with zeros by a 1-digit number, first ­multiply the digits without the zeros. Then, place as many zeros at the end of the product as the z­ eros at the end of the number b­ eing multiplied. © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 69

Exercise 5 1. Write the missing numbers. a) 2 tens × 4 = tens 20 × 4 = 50 × 9 = b) 5 tens × 9 = tens 600 × 7 = 800 × 2 = c) 6 hundreds × 7 = hundreds SCHOLASTIC 300 × 5 = d) 8 hundreds × 2 = hundreds 600 × 8 = 2. Multiply. 30 × 5 = a) 3 × 5 = b) 6 × 8 = 60 × 8 = Practice 3 1. Multiply mentally. a) 10 × 2 = b) 40 × 3 = c) 70 × 9 = f) 50 × 7 = d) 60 × 5 = e) 80 × 6 = c) 500 × 2 = 2. Multiply mentally. b) 600 × 4 = f) 900 × 5 = a) 200 × 7 = e) 700 × 8 = d) 800 × 3 = I know how to m ultiply tens or hundreds by a 1-digit number 70 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

4 Division 4.1  Dividing tens or hundreds a) Divide 12 by 3. 1111 12 ÷ 3 = 4 1 1 1 1 1111 SCHOLASTIC b) Divide 120 by 3. 10 10 10 10 120 ÷ 3 = 12 tens ÷ 3 10 10 10 10 10 10 10 10 = 4 tens = 40 c) Divide 1200 by 3. 1200 ÷ 3 = 12 hundreds ÷ 3 100 100 100 100 = 4 hundreds 100 100 100 100 100 100 100 100 = 400 When dividing a number ending with zeros by a 1-digit number, first divide the digits without the zeros. Then, place as many zeros at the end of the quotient as at the end of the number b­ eing divided. © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 71

Exercise 6 1. Write the missing numbers. a) 6 tens ÷ 2 = tens 60 ÷ 2 = 140 ÷ 7 = b) 14 tens ÷ 7 = tens 500 ÷ 5 = 2700 ÷ 9 = c) 5 hundreds ÷ 5 = hundred 800 ÷ 4 = SCHOLASTIC d) 27 hundreds ÷ 9 = hundreds 2. Divide. a) 8 ÷ 4 = 80 ÷ 4 = b) 9 ÷ 3 = 90 ÷ 3 = 900 ÷ 3 = Practice 4 b) 50 ÷ 5 = c) 160 ÷ 8 = e) 630 ÷ 7 = f) 720 ÷ 9 = 1. Divide mentally. a) 90 ÷ 9 = c) 180 ÷ 6 = d) 240 ÷ 4 = f) 810 ÷ 9 = 2. Divide mentally. b) 200 ÷ 4 = a) 300 ÷ 5 = e) 640 ÷ 8 = d) 490 ÷ 7 = I know how to divide tens or hundreds by a 1-digit number 72 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

Chapter Review 1. Add mentally. a) 87 + 36 b) 74 + 98 c) 65 + 45 d) 77 + 84 g) 94 + 98 h) 97 + 99 e) 66 + 79 f) 85 + 67 d) 84 – 36 h) 80 – 54 2. Subtract mentally. 900 a) 95 – 68 b) 81 – 54 c) 67 – 29 g) 90 – 65 = 39 e) 70 – 58 f) 60 – 47 = 84 SCHOLASTIC 3. Multiply. Then, complete the table. × 90 110 a) 3 b) 7 c) 9 4. Divide. Then, complete the table. Quotient a) 320 ÷ 4 b) 360 ÷ 6 c) 400 ÷ 5 d) 300 ÷ 6 e) 810 ÷ 9 f) 720 ÷ 8 5. Fill in the missing numbers. a) 67 – = 47 b) 79 – d) 26 + c) 58 + = 90 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 73

6. Two of the numbers below when added make 36. Which are the two numbers? 21 12 25 24 7. Anju saves ` 800 per month. She puts the money equally in 4 money boxes to buy gifts for each of her family members. How much money will Anju save in a month for each family member? SCHOLASTIC 8. Kian multiplied a number by 3. He then added 24 to it. He got 84 as the sum. Find the number he started with. 9. What is the missing number? 3 13 23 33 5 35 7 27 19 21 ? 10. Mona buys a pencil case and a glue stick. The pencil case costs ` 75. The glue stick costs ` 30. Mona gives a two-hundred-rupee note to the shopkeeper and gets back ` 75 as change. Use mental calculation to explain to the shopkeeper that the amount of change that Mona receives is incorrect. Maths Lab Activity Using mental strategies Work in groups of four. Each group will think of a number and write an addition and subtraction sentence for it. Take turns to read aloud the sentences created to the other groups. The rest of the students should calculate the answers mentally. For example, © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 For 72, you may write: 60 + 12 80 – 8 74

34 56 611LenFgrathctions Let’s Revise 1. Fill in the blanks with metres or centimetres. a) We use to measure shorter lengths. b) We use to measure longer lengths. SCHOLASTIC 2. Estimate the following distances and lengths. Then, measure the distances and lengths using a metre ruler or a centimetre ruler. Actual Estimate measure a) Distance from the first about m m desk to the board m m b) Distance from the first about cm cm desk to the door cm cm c) Length of your eraser about d) Length of your pencil box about 3. Circle the appropriate unit of measurement for each of the following. a) A school bus is 11 metres / centimetres long. b) A fork is about 15 metres / centimetres long. c) A giraffe is about 5 metres / centimetres tall. d) A pencil is 15 metres / centimetres long. 75 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

1  Metres and Centimetres 1.1  Length in metres and centimetres a) 10 20L30 40 50 60A70 80 90 100 STIC 90 100 cm cm 0 10 20 30 40 50 60 70 80 90 100 cm 100 cm = 1 m The guitar is as long as the metre ruler. 1 metre is 100 times as It is 1 metre or 100 centimetres long. long as 1 centimetre. 1 metre = 100 centimetres 1 m = 100 cm b) 80 90 80 cm 10 20 30 40 50 60O70 80 90 100 0 cm The height of the bookcase is more than 1 metre. 1 m The height of the bookcase is 1 metre 80 centimetres. 0SCH c) A mango tree has a height of 3 metres 65 centimetres. What is its height in c­ entimetres? 3 m = 300 cm 3 m 65 cm 1 m = 100 cm 3 m = 300 cm 65 cm ×3 ×3 3 m 65 cm = 300 cm + 65 cm = 365 cm The height of the mango tree is 365 centimetres. 76 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

d) A rope is 274 centimetres long. What is its length in metres and centimetres? 200 cm = 2 m 100 cm = 1 m 274 cm 74 cm ×2 ×2 200 cm = 2 m 274 cm = 2 m + 74 cm = 2 m 74 cm SCHOLASTICThe length of the rope is 2 metres 74 centimetres. Exercise 1 1. Estimate the following distances and lengths. Then, measure the distances and lengths using a metre ruler or a measuring tape. Estimate Actual measure a) Height of m cm classroom door about m m cm m cm b) Distance from the about m m cm cupboard to the door c) Length of the about m teacher’s table d) Distance from the board to the door about m 2. Express in centimetres. a)   2 m 41 cm = cm b) 4 m 3 cm = cm 2m= cm  4 m = cm 2 m 41 cm 4 m 3 cm 41 cm  cm 2 m 41 cm = cm + 41 cm 4 m 3 cm = cm + cm cm 77 = cm = © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

3. Express in metres and centimetres. b) 672 cm = m cm a)  457 cm = m cm   672 cm  400 cm = m 600 cm = m 457 cm  cm cm m + cm 457 cm = m + cm  672 cm = m cm SCHOLASTIC = m cm = 1.2  Comparing lengths in metres and centimetres The lengths of some objects are shown below. table fish tank projector screen 2 m 38 cm 183 cm 2 m 13 cm Express the lengths in centimetres. The length of the table is 2 m 38 cm = 238 cm. The length of the fish tank is 183 cm. The length of the projector screen is 2 m 13 cm = 213 cm. Compare the lengths, 238 cm, 183 cm and 213 cm. First, compare the hundreds. 1 hundred is smaller than 2 hundreds. So, the fish tank is the shortest. Next, compare the tens in 238 and 213. 3 tens is greater than 1 ten. So, the table is the longest. If we arrange the objects in decreasing order of their lengths, we have: table, projector screen, fish tank. (longest) 78 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

Exercise 2 1. Compare the lengths of the objects. Then, fill in the blanks. 2 m 12 cm 304 cm 258 cm whiteboard motorcycle truck SCHOLASTIC a) The length of the motorcycle is centimetres. b) The whiteboard is shorter than the . c) The is the longest. d) Arrange the objects in increasing order of their lengths. , , (shortest) Practice 1 1. Express in centimetres. a) 6 m = cm b) 1 m 7 cm = cm d) 5 m 82 cm = cm c) 3 m 90 cm = cm f) 6 m 16 cm = cm cm e) 4 m 21 cm = 2. Express in metres and centimetres. a) 200 cm = m cm b) 130 cm = m cm c) 516 cm = m cm d) 804 cm = m cm e) 310 cm = m cm f) 501 cm = m cm 3. Circle the correct answer. a) 4 m 26 cm is longer than / equal to / shorter than 462 cm. b) 705 cm is longer than / equal to / shorter than 7 m 5 cm. c) 2 m 34 cm is longer than / equal to / shorter than 324 cm. d) 550 cm is longer than / equal to / shorter than 5 m 5 cm. © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 79

4. Arrange the lengths in decreasing order. a)  3 m 94 cm 311 cm 2 m 19 cm 349 cm b)  4 m 54 cm 445 cm 5 m 44 cm 405 cm c)  612 cm 6 m 2 cm 6 m 20 cm 621 cm I know how to express metres and centimetres in measure length in metres and centimetres centimetres and vice versa c ompare lengths in metres and centimetres SCHOLASTIC 2  Kilometres and Metres 2.1  Length in kilometres and metres a) A football field is about 100 metres long. 100 m The total length of 10 such football fields is about 1000 metres or 1 kilometre. The kilometre is a unit of length. We write km 1 kilometre is for kilometre. 1000 times as We use kilometres to measure long distances. long as 1 metre. 1 kilometre = 1000 metres 1 km = 1000 m 80 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

b) A cargo train has a length of 2 kilometres 198 metres. What is its length in metres? 2 km = 2000 m 1 km = 1000 m ×2 2 km 198 m 198 m ×2 2 km = 2000 m 2 km 198 m = 2000 m + 198 m  = 2198 m The length of the cargo train is 2198 metres. SCHOLASTIC c) The distance from Nisha’s house to the city centre is 6320 metres. What is the distance in kilometres and metres? 6000 m = 6 km 1000 m = 1 km 6320 m 320 m ×6 ×6 6000 m = 6 km 6320 m = 6 km + 320 m = 6 km 320 m The distance from Nisha’s house to the city centre is 6 kilometres 320 metres. Exercise 3 1. Circle the most appropriate unit to measure each of the following. a) Length of a bus b) Distance between two cities cm   m   km cm   m   km c) Height of a water bottle d) Height of a waterfall cm   m   km cm   m   km © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 81

2. Express in metres. m b) 1 km 216 m = m a) 3 km 540 m = 3 km = m 1 km = m 3 km 540 m 1 km 216 m 540 m m 3 km 540 m = m + 540 m 1 km 216 m = m + m SCHOLASTIC =m =m 3. Express in kilometres and metres. a) 2180 m = km m b) 4795 m = km m km 2000 m = 4000 m = km 2180 m 4795 m m m 2180 m = km + m 4795 m = km + m = km m = km m 2.2  Comparing lengths in kilometres and metres The table shows the heights of some of the world’s highest mountains. Name Height Kanchenjunga 8 km 586 m Kamet 7756 m Nanda Devi 7 km 816 m Express the heights in kilometres and metres. The height of Kanchenjunga is 8 kilometres 586 metres. The height of Kamet is 7756 metres or 7 kilometres 756 metres. The height of Nanda Devi is 7 kilometres 816 metres. 82 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

Kanchenjunga is taller than Kamet and Nanda Devi. 8 km > 7 km It is the tallest mountain. 756 m < 816 m Kamet is shorter than Nanda Devi. It is the shortest mountain. If we arrange the mountains in increasing order of their heights, we have: Kamet, Nanda Devi, Kanchenjunga. (shortest) Exercise 4 SCHOLASTIC 1. The map below shows the distance of an aeroplane from different places. Chandigarh Dehradun 230 km 193 km 950 m 9050 m Delhi 160 km 512 m Agra a) The distance of the aeroplane from Dehradun airport is kilometres metres. b) The distance of the aeroplane from Delhi airport is kilometres metres. c) The aeroplane is closer to as compared to Agra. d) The aeroplane is farther from as compared to Dehradun. e) If the aeroplane needs to make an emergency landing, it should land at . f) Arrange the distance of the aeroplane from the different places in decreasing order. , , , (longest) © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 83

The following mountains are arranged in the order of tallest to shortest: Mount Ararat, Mount Kinabalu and Mount Cameroon. Match the mountains with their heights – 4 km 95 m, 4040 m, 5 km 137 m. Practice 2 1. Fill in the blanks with centimetres, metres or kilometres. SCHOLASTIC a) The length of a thumb is about 5 . b) Dan jogs about 3 every day after work. c) The length of a kite string is about 25 . 2. Look at the picture. Then, fill in the blanks. hospital mall • Anil’s home • 25 km 47 km • • 21 km 32 km swimming pool • stadium a) The distance between Anil’s home to the hospital is ­kilometres. b) The distance between Anil’s home to the swimming pool is ­kilometres. c) The distance between the stadium to the hospital is 84 kilometres. d) The distance between the swimming pool to the stadium is ­kilometres. © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

e) The distance between Anil’s home and the mall is kilometres shorter than the distance between his home and the swimming pool. f) Anil travelled from his home to the hospital and back to his home. He travelled a total distance of kilometres. 3. Express in metres. m b) 2 km 325 m = m a) 7 km = m d) 5 km 9 m = m c) 8 km 40 m = m f) 5 km 648 m = e) 2 km 345 m = m SCHOLASTIC 4. Express in kilometres and metres. a) 5000 m = km m b) 3291 m = km m c) 1064 m = km m d) 8003 m = km m e) 3648 m = km m f) 8274 m = km m 5. Circle the correct answer. a) 6079 m is longer than / equal to / shorter than 6 km 79 m. b) 4 km 200 m is longer than / equal to / shorter than 4002 m. c) 1933 m is longer than / equal to / shorter than 19 km 33 m. d) 7 km 830 m is longer than / equal to / shorter than 7839 m. 6. Arrange the lengths in increasing order. a) 8 km 900 m 9080 m 8 km 9 m 9800 m 8 km 205 m b) 7204 m 7 km 420 m 8520 m 7. Arrange the lengths in decreasing order. a) 5160 m 6 km 150 m 5 km 161 m 6015 m 5104 m b) 4759 m 4 km 975 m 4097 m I know how to e xpress kilometres and metres in metres m easure length in kilometres and vice versa  c ompare lengths in kilometres and metres © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 85

3  Word Problems Every week, Mr Malhotra travels a total distance of 745 kilometres from his home to his office and back from his office to his home. If he works 5 days a week and travels the same distance each day, how far does he travel each day? 1 Understand Mr Malhotra travels 745 kilometres every week. the problem. He works 5 days a week and he travels the same ­distance each day. I have to find how far Mr Malhotra travels each day. SCHOLASTIC 2 Plan Draw a bar model to solve the problem. what to do. 3 Work out the 745 km Answer. ? 745 km ÷ 5 = 149 km He travels 149 kilometres each day. 4 Check 149 km × 5 = 745 km if your answer My answer is correct. is correct. 1 . Understand 2 . Plan 3 . Answer 4 . Check 86 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0

Exercise 5 Solve the word problems. Draw bar models to help you. 1 . Understand 2 . Plan 3 . Answer 4 . Check 1. Shilpi has a red ribbon that is 425 centimetres long. She also has a yellow ribbon that is 173 centimetres long. What is the total length of the two ribbons? 2. Pole A has a length of 512 centimetres. Pole B is 247 centimetres shorter than Pole A. Find the length of Pole B. 3. Joy went on an 8-day road trip. He travelled 124 kilometres each day. How far was his road trip? 4. A rope that is 378 metres long is cut into 7 equal pieces. What is the length of each piece? SCHOLASTIC I know how to solve 1-step word problems on length or distance Chapter Review 1. Express in centimetres. a) 6 m 6 cm       b)  6 m 60 cm       c)  6 m 61 cm d) 3 m         e)  3 m 3 cm        f)  3 m 30 cm 2. Express in metres and centimetres. a) 200 cm        b)  240 cm          c)  385 cm d) 101 cm      e)  110 cm          f)  505 cm 3. Express in metres. a) 1 km 400 m     b)  2 km 270 m       c)  5 km 5 m d) 1 km 90 m      e)  3 km 900 m     f)  1 km 1 m © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0 87

4. Express in kilometres and metres. a) 2005 m b) 7080 m c) 1100 m f) 2801 m d) 8256 m e) 3082 m 5. Arrange the lengths in increasing order. a) 340 cm 3 m 45 cm 3 m 54 cm 304 cm 1 km 520 m b) 1025 m 1250 m 1 km 50 m 215 cm c) 512 m 5 m 2 cm 2 m 51 cm SCHOLASTIC 6. Arrange the lengths in decreasing order. a) 9900 m 9990 m  9099 m   9 km 909 m b) 7690 m 7 km 69 m 6 km 790 m 6 km 79 m c) 590 cm 602 cm 5 m 19 cm 6 m 25 cm 7. The height of a door is 2 metres 4 centimetres. The height of the wall from the top of the door to the ceiling is 670 centimetres. a) What is the height of the door in centimetres? b) What is the height of the room from the bottom of the door to the ceiling? 8. Rafi and 3 of his friends took part in a half marathon relay. They ran a ­total distance of 21 kilometres. Rafi ran 6 kilometres. If each of his 3 friends ran the same distance, how far did each friend run? 9. The height of a rectangular door of a classroom is 198 centimetres. Its width is 76 centimetres. The opposite sides of the door are equal in length. What is the total length of all 4 sides of the door? 10. Nisha’s friends plan to make a big greeting card and an envelope on her birthday. They want to know if a greeting card of length 125 centimetres can fit into an envelope of length 1 metre 29 centimetres. Explain to Nisha’s friends how they can find this out. 88 © 2019 Scholastic Education International (S) Pte Ltd ISBN 978-93-52750-16-0