Ascend Maths G3 TB Part 1_NS.pdf 1 8/2/2023 1:10:06 PM 3Grade MATHEMATICS TEXTBOOK Part - 1 Name: _________________________________________ Section: ________________ Roll No.: ______________ School: ________________________________________
TEXTBOOK FEATURES Art-Integrated Learning Lesson plans provided for art-integrated learning Maths Lab Activities that help students understand abstract concepts through concrete application Student Reflection Maths Munchies Captures student's perception of their Aims at improving speed understanding of a lesson of calculation and problem solving with interesting The blood in our body also has a unit of measurement called ‘pint’ 9facts, tips or tricks or ‘unit’. An adult body contains 8 to 10 pints of blood. Multiply 2-digit numbers by 1 pint is equal to 473 mℓ. 2, 3, 4, 5 and 6. Therefore, our body has 3784 mℓ A) 56 × 3 B) 23 × 2 C) 77 × 6 to 4730 mℓ of blood. 8 Drill Time Draw the hands of a clock to show the given time Additional practice questions at the end of A) 1:15 B) 6:15 every concept I Apply I Explore 7 Connects the concept to real-life situations by enabling Encourages students to 6 students to apply what has extend the concept to been learned through practice questions advanced scenarios using higher order thinking skills Kiran weighs 12785 g and making a tangram 2 Farida’s father bought her a Venu weighs 11 kg 750 g. recognising 3D shapes and their shirt for ₹ 335 and a skirt for ₹ Who weighs more faces and edges 806. Farida wants to find how and by how many grams? much her father had spent in I Will Learn About all. How do you think she can SKILL-BASED find that? Indicates the learning I Think 1outcomes to be covered in Introduces the concept and the chapter arouses curiosity among students Ascend_G3_Maths_Book_TB_Part1.indb 2 8/3/2023 11:36:54 AM
Science Fun Multiplication is used in many situations in The human body has 206 bones in our day-to-day activities for calculating all. If both hands have 54 bones, time, distance, money to be paid in a then how many bones are there in departmental store, the area of a room the other parts of the body? and so on. Encourage your child to actively engage in these scenarios and Connect the Dots help you with the calculations. A multidisciplinary section to A Note to Parent connect the lesson theme with Ideas to engage parents in 10 other subjects out-of-classroom learning of Solve the following: 11their child to reinforce the a) 12 ÷ 4 b) 648 ÷ 8 c) 744 ÷ 4 concepts Train My Brain D C In the given rectangle, AB, BC, CD Checks for the acquisition of and DA are called its sides. There are 5both skills and knowledge . lines joining A to C and B to D. These lines named AC and BD are called through questions A B the diagonal of the rectangle. I Remember and Understand 4 Explains the fundamental aspects of the concept in detail, and in an age-appropriate and engaging manner Let us revise the concept about money. INQUIRY-BASED Identify the value of the given coin. Concepts organised using a question-answer (A) ₹1 (B) ₹2 (C) ₹5 (D) ₹10 approach to foster a mindset of inquiry and reasoning I Recall Reflection Time! Activates the pre-requisite Thought-provoking questions to encourage 3knowledge needed for the reflection on the concept and on how it is related to the student's life, experiences and concept covered previously the world around Ascend_G3_Maths_Book_TB_Part1.indb 3 8/3/2023 11:36:54 AM
CONTENTS 1) 1.1) Vertices and Diagonals of Two-dimensional Shapes Theme Art-Integrated Learning Skill-Based 01 12 Geometry 2) Patterns and Patterns 2.1) Patterns in Shapes and Numbers Inquiry-Based 3) Numbers 19 Theme 3.1) Count by Thousands Skill-Based 26 3.2) Compare 4-digit Numbers Numbers Skill-Based 4) Addition 34 37 4.1) Estimate the Sum 42 of Two Numbers Inquiry-Based 4.2) Add 3-digit and 4-digit Numbers Theme Art-Integrated Learning Skill-Based Number 4.3) Add 2-digit Numbers Operations Mentally Inquiry-Based Ascend_G3_Maths_Book_TB_Part1.indb 4 8/3/2023 11:36:56 AM
5) Subtraction 46 48 5.1) Estimate the Difference 55 between Two Numbers Inquiry-Based 5.2) Subtract 3-digit and 4-digit Numbers Skill-Based 5.3) Subtract 2-digit Numbers Mentally Inquiry-Based Theme Number Operations 6) Multiplication 6.1) Multiply 2-digit Numbers Art-Integrated Learning Skill-Based 59 64 6.2) Multiply 3-digit Numbers by 1-digit 70 and 2-digit Numbers Skill-Based 74 6.3) Double 2-digit and 3-digit Numbers Mentally Inquiry-Based 8/3/2023 11:36:57 AM Maths Lab 73 Student Reflection Ascend_G3_Maths_Book_TB_Part1.indb 5
CLASSKLAP AND NCF Education plays a crucial role in shaping the future of our children and 251 empowering them to become well-rounded individuals. The latest National 4 3 Curriculum Framework (NCF), furthering the vision of the National Education Policy (NEP) 2020, focuses on fostering creativity, critical thinking, and problem-solving skills while also nurturing values of inclusivity, collaboration and democratic citizenship. The development of foundational literacy and numeracy is also a core goal of the NCF. ClassKlap by Eupheus partners with schools, supporting them through the steps of planning, teaching, learning, personal revision and assessment to equip students with the desired knowledge and skills relevant to the 21st century. The present series is a learning resource that not only meets the requirements of the NCF but also engages and captivates young minds. Here are some salient features of this series. NCF-aligned learning tool Description Skill-based lessons in textbook and workbook Lessons are structured as per Bloom’s Revised Taxonomy Inquiry-based lessons (Remember-Understand-Apply-Analyse-Evaluate-Create) and LSRW in textbook and (Listening-Speaking-Reading-Writing) skills for English. workbook Lessons are structured based on a Socratic approach using a Highlight features question-answer format, aiming at discovery-based learning as per NCF guidelines. Exploratory activities in the workbook facilitate holistic Practice Worksheets learning of the skills and concepts and foster a sense of curiosity and exploration among students. Features such as Poetry Appreciation, Maths Lab, Think Like a Scientist, Life Skills and others help learners engage in research, application-oriented learning and the development of scientific temper; Student Reflection sheets foster the skill of reflecting on one’s own learning progress. Practice Worksheets are aligned with the goals of sharpening critical thinking, evidence-based thinking and higher-order thinking skills, as per NCF guidelines. The books contain the following overarching features recommended in the NCF: a logical and spiralling progression of frameworks adopted for Grammar, Maths and EVS inclusive representation of gender and diversity for the heterogeneous Indian classroom learner-centred content, vibrant illustrations, diagrams and photographs along with age-appropriate language a variety of question types with scaffolded and independent practice to meet the needs of different students We are confident that this series will serve as a valuable tool to accomplish the aims of the NCF and help transform teaching-learning in classrooms. We sincerely hope that our young learners develop genuine curiosity and love for learning. Ascend_G3_Maths_Book_TB_Part1.indb 6 8/3/2023 11:37:00 AM
1 Shapes I Will Learn identifying 2D shapes with straight and curved lines About identifying sides, corners and diagonals making a tangram recognising 3D shapes and their faces and edges 1.1: Vertices and Diagonals of Two-dimensional Shapes I Think There is a paper folding activity in Farida’s class. Her teacher asked the students to fold the paper across the vertices or the diagonals. How will Farida fold the paper? 1.1 I Recall We have learnt various shapes formed by straight lines or curved lines. Let us recall them. AB A BA B line line segment ray 1 Ascend_G3_Maths_Book_TB_Part1.indb 1 8/3/2023 11:37:01 AM
horizontal lines vertical lines slant lines curved lines The straight and curved lines help us make closed and open figures. Figures which end at the point from where they start are called closed figures. Figures which do not end at the point from where they start are called open figures. closed figures open figures Try this! Write ‘open figure’ or ‘closed figure’ in the given blanks. ____________ ____________ ____________ ____________ Shapes such as rectangle, triangle, square and circle that can be drawn flat on a piece of paper are called two-dimensional shapes. Their outlines are called two-dimensional figures. In short, they are called 2D figures. 2 Shapes Ascend_G3_Maths_Book_TB_Part1.indb 2 8/3/2023 11:37:01 AM
Identify the following shapes and separate them as 1D or 2D shapes. One has been done for you. Object Shape Name of the shape 1D or 2D Triangle 2D 1.1 I Remember and Understand D C As we have already learnt various shapes, let us now name their parts. Consider a rectangle ABCD as shown. In the given rectangle, AB, BC, CD and DA are called its A B sides. There are lines joining A to C and B to D. These lines named AC and BD are called the diagonals of the rectangle. Points A, B, C and D where two sides of the Vertex: The point where at least rectangle meet are called the vertices. two sides of a figure meet is called a vertex. The plural of A square also has sides, diagonals and vertices. vertex is vertices. Diagonal: A straight line inside Note: A triangle and a circle do not have any a shape that joins the opposite diagonals. vertices is called a diagonal. Shapes 3 Ascend_G3_Maths_Book_TB_Part1.indb 3 8/3/2023 11:37:01 AM
Try this! Complete the table with vertices, sides and diagonals of the given different shapes. One has been done for you. Shape Vertices Sides Diagonals DC A, B, C, D AB, BC, CD, DA AC, BD A B S R ___, ___, ___, ___ ___, ___, ___, ___ _____, _____ PQ Y Z X ___, ___, ___, ___ ___, ___, ___, ___ _____, _____ W Train My Brain Name the given figures and find the number of their vertices and diagonals. a) b) c) 1.1 I Apply We know that a 2D shape has length and breadth. Let us now learn A to find the number of sides of a 2D shape. Consider a triangle as shown. The given triangle has 3 sides named as AB, BC and CA. We can also name them as BA, CB and AC. B C Shapes 4 Ascend_G3_Maths_Book_TB_Part1.indb 4 8/3/2023 11:37:02 AM
The different number of markings on the sides of the triangle show that the lengths of all the 3 sides are different. If all the sides have the same number of markings, we can say that the lengths of all the 3 sides are the same. Let us now find the number of sides of a few 2D shapes and name them. Shape Name of the shape Number of sides Names of sides SR PQ, QR, RS, SP AB, BC, CD, DA Square 4 (All sides are equal.) AB, BC, CA PQ D C Rectangle 4 B Triangle (Opposite sides are A A equal.) 3 (All sides are equal in this case.) BC We find objects of various shapes around us. Complete the following table by writing the basic shapes, number of the vertices and diagonals of the given objects. Object Basic shape Number of vertices Number of diagonals Shapes 5 Ascend_G3_Maths_Book_TB_Part1.indb 5 8/3/2023 11:37:02 AM
Object Basic shape Number of vertices Number of diagonals Tangram A tangram is a Chinese geometrical puzzle. It consists of a 36 square that is cut into pieces as shown in the given figure. To create different shapes, we arrange these tangram pieces 4 1 with their sides or vertices touching one another. 7 5 Let us make our own tangram. 2 Materials needed: a square sheet of paper a pair of scissors a ruler (optional) Procedure: Figure Steps Step 1: Fold the square sheet of paper as shown. Step 2: Cut the square into two triangles, A across the fold. B Step 3: Cut one of the triangles obtained A1 in step 2, into two equal parts. We get two 2 smaller triangles as shown. 6 Shapes Ascend_G3_Maths_Book_TB_Part1.indb 6 8/3/2023 11:37:03 AM
Steps Figure Step 4: Fold the bigger triangle as shown. B Step 5: Unfold this piece and cut it across the 3 fold. We get one more triangle. 4 Step 6: Fold the boat-shaped piece from one end as shown. We get a triangle again on cutting at the fold. Step 7: Fold the remaining part of the paper 5 as shown. We get a square on cutting at the fold. Step 8: Fold the remaining paper again as 6 shown. We now get one more triangle on 7 cutting at the fold. We, thus, get the seven pieces of the tangram. Step 9: Colour these shapes using different colours. You can use these tangram pieces to make different shapes. Shapes 7 Ascend_G3_Maths_Book_TB_Part1.indb 7 8/3/2023 11:37:03 AM
1.1 I Explore Observe the given figure. It looks like a box. Each side of the box is a E F B square. A In the figure, AB is the length and BF is the breadth of the box. AD is called the height of the box. So, this shape has three dimensions - HG length, breadth and height. DC Such shapes are called three-dimensional shapes or 3D shapes or solid cube shapes. In the figure, • The points A, B, C, D, E, F, G and H are called vertices. • The lines AB, BC, CD, DA, BF, FE, EA, CG, GH, HD, HE and GF are called edges. • The squares ABCD, ABFE, BFGC, GCDH, EFGH and AEHD are called faces. Solid shapes with all flat square faces are called cubes. Let us learn how to draw a cube in a few simple steps. Steps Figure Step 1: Draw a square ABCD. DC Step 2: Draw another square EFGH cutting A B square ABCD as shown. H G Step 3: Join DH, AE, BF and CG. D C 8 E F A B Ascend_G3_Maths_Book_TB_Part1.indb 8 H G D C E F A B Shapes 8/3/2023 11:37:03 AM
A few other such three-dimensional shapes are cuboids and cones. Solid shapes with six flat rectangular faces are called cuboids. A solid shape with a circular base, a vertex and a curved Cuboid Cone surface is called a cone. Try this! Draw a cuboid and a cone showing the formation of the figure in steps. Shape Step 1 Step 2 Step 3 Cuboid Cone Drill Time 1.1: Vertices and Diagonals of Two-dimensional Shapes 1) Find the number of vertices and diagonals of the following shapes: a) b) c) d) e) Shapes 9 Ascend_G3_Maths_Book_TB_Part1.indb 9 8/3/2023 11:37:03 AM
Drill Time 2) Draw the 2D shapes using given hints. a) I am a closed figure. I have three sides and three corners. b) I have four equal sides and four corners. c) I am a closed plane figure. I have no corners or sides. Maths Munchies We can use tangrams to make many shapes such as: Boat Candle Rocket Can you make a house with the following tangrams? You can use the same shape twice. Connect the Dots Social Studies Fun We can see 2D shapes such as rectangles, squares, circles and 3D shapes such as cubes and cuboids in the buildings in our neighbourhood. Can you identify some shapes in your neighbourhood? 10 Shapes Ascend_G3_Maths_Book_TB_Part1.indb 10 8/3/2023 11:37:04 AM
English Fun Try drawing a square while reciting the rhyme. From the bottom to the top, straight across right and then you stop. Straight down to the bottom again, across left and stop where you began. If the lines are the same size, then a square is formed for you a surprise. A Note to Parent Take your child to public places such as hospitals, markets and religious places. Help them name the 3D shapes that are commonly seen on these structures. Shapes 11 Ascend_G3_Maths_Book_TB_Part1.indb 11 8/3/2023 11:37:04 AM
2 Patterns I Will Learn identifying and creating patterns in shapes and numbers About identifying and creating growing patterns in shapes and numbers 2.1: Patterns in Shapes and Numbers Things around us display different patterns. Window grill Rangoli Cloth pattern Do you know what a pattern is? A pattern consists of a series of shapes or numbers that are arranged in a specific order and they repeat themselves based on some rule. 12 8/3/2023 11:37:06 AM Ascend_G3_Maths_Book_TB_Part1.indb 12
Look at the following patterns. These are made up of lines and shapes. a) b) c) d) Now complete the patterns below. Do we have patterns in numbers too? We have seen that patterns are formed by repeating shapes in a particular way. Similarly, we can also create patterns using numbers. Few of the common patterns in numbers are that of even numbers and odd numbers. An even number always ends with 2, 4, 6, 8 or 0. You can make a pattern with even numbers by adding 2 to the previous even number. For example, 2 + 2 = 4; 4 + 2 = 6; 6 + 2 = 8 and so on. An odd number always ends with 1, 3, 5, 7 or 9. You can make a pattern with odd numbers by adding 2 to the previous odd number. For example, 1 + 2 = 3; 3 + 2 = 5; 5 + 2 = 7 and so on. Patterns 13 Ascend_G3_Maths_Book_TB_Part1.indb 13 8/3/2023 11:37:07 AM
Colour the even numbers in green and the odd numbers in yellow. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Look at this set of numbers. Do you think there is a pattern in this set? 2, 5, 7, 10, 14 …. What are growing patterns? A growing pattern is a pattern where a unit (a number or shape) is added every time the sequence repeats. Look at the following growing patterns in shapes and complete them. 14 Patterns Ascend_G3_Maths_Book_TB_Part1.indb 14 8/3/2023 11:37:08 AM
Do we have growing patterns in numbers too? Growing patterns in numbers are formed by units (or terms) that increase by a certain number. We can find this number by subtracting the 2nd unit from the 1st, the 3rd from the 2nd, and so on. Let us look at an example first, and try completing the next two growing patterns. Solved: Pattern 1 Solve: Pattern 2 Solve: Pattern 3 20, 30, 40, 50… 100, 200, 300… 11, 21, 31, 41 … What comes next? What comes next? What comes next? The unit by which the growing pattern is increasing can be found by subtraction: 30 – 20 = 10 So, the rule is: the pattern increases by 10. Therefore, the next unit is: 50 + 10 = 60 Now, complete each pattern by writing the next three terms. a) 9, 29, 49, 69, _____, _____, _____ b) 13, 23, 33, 43, _____, _____, _____ c) 5, 10, 15, 20, _____, _____, _____ F ind the rule followed in the given patterns. Then, write the next three terms for each of them. a) 12, 24, 36, _____, _____, _____ b) 1 + 2 = 3, 2 + 3 = 5, 3 + 4 = 7, ____________, ____________, ____________ Patterns 15 Ascend_G3_Maths_Book_TB_Part1.indb 15 8/3/2023 11:37:08 AM
Reflection Time! 1) Take a look around the room you are in right now. Identify a few patterns that you see in the objects or things in the room. 2) Can you look at this growing pattern and draw what comes next? Drill Time 2.1: Patterns in Shapes and Numbers 1) Complete the following patterns. a) _________ _________ __________ b) ____________ _____________ c) ___________ __________ d) ____________ ____________ e) ________________ ______________ 16 Patterns Ascend_G3_Maths_Book_TB_Part1.indb 16 8/3/2023 11:37:15 AM
Drill Time f) ___________ __________ 2) Fill the blanks with the next two terms of the given patterns. a) 122, 133, 144, ______, ______ b) 303, 304, 305, ______, ______ c) 40, 42, 44, ______, ______ d) 8, 24, 40, ______, ______ e) 35, 30, 25, ______, ______ f) 82, 72, 62, ______, ______ Maths Munchies 1 Pascal’s triangle 11 In the given triangle, each number is the 12 1 sum of the two numbers above it. This is 13 31 known as Pascal’s triangle. 14641 Pascal’s triangle is a triangular number 1 5 10 10 5 1 pattern named after Blaise Pascal, a French mathematician. 1 6 15 20 15 6 1 1 7 21 35 35 21 7 1 Patterns 17 Ascend_G3_Maths_Book_TB_Part1.indb 17 8/3/2023 11:37:15 AM
Connect the Dots Science Fun We see patterns all around us. Flowers, leaves, stripes on animals and so on have patterns. Here are a few pictures in which we can observe patterns that are found in nature. English Fun Little Frog A B In poems, we see a I saw a little frog, A certain pattern or a He was cuter than can be, B rhyming scheme. In He was sitting on a log, this poem, we see the And I'm sure he croaked at me! pattern of rhyming in alternate lines. A Note to Parent We observe different patterns every day. Here is an activity you can do with your child with some inspiration from these patterns. Make a wall hanging which can be used to brighten up your room! This can be done by cutting square sheets of different co- loured paper and pasting it on a base sheet. If you have waste piece of cloth, it can also be woven into a bed sheet. 18 Patterns Ascend_G3_Maths_Book_TB_Part1.indb 18 8/3/2023 11:37:17 AM
3 Numbers I Will Learn writing 4-digit numbers with place value chart About writing the standard and the expanded forms of a number comparing and ordering numbers identifying and forming the greatest and the smallest number 3.1: Count by Thousands Farida went to buy one of the toy cars shown. She I Think could not read the price on one of the cars. Can you read the price on both the cars and understand `1937.00 what they mean? `657.00 3.1 I Recall We know that 10 ones make a ten. Similarly, 10 tens make a hundred. Let us now count by tens and hundreds as: Counting by 10s: 10, 20, 30, 40, 50, 60, 70, 80 and 90 Counting by 100s: 100, 200, 300, 400, 500, 600, 700, 800 and 900 19 Ascend_G3_Maths_Book_TB_Part1.indb 19 8/3/2023 11:37:18 AM
When we multiply a digit by the value of its place, we get its place value. Using place values, we can write a number in its expanded form. Let us answer these to revise the concept. a) The number for two hundred and thirty-four is _____________. b) In 857, there are _______ hundreds, _______ tens and _______ ones. c) The expanded form of 444 is _______________________. d) The place value of 9 in 493 is _____________. e) The number name of 255 is _______________________________________. 3.1 I Remember and Understand To know about 4-digit numbers, we count by thousands using boxes. Suppose shows 1. Ten such boxes show a 10. So, = 10 ones = 1 ten Similarly, 10 such strips show 10 tens or 1 hundred. = 10 tens = 1 hundred 20 Numbers Ascend_G3_Maths_Book_TB_Part1.indb 20 8/3/2023 11:37:21 AM
= 1 hundred = 100 = 2 hundreds = 200 = 3 hundreds = 300 = 4 hundreds = 400 In the same way, we get 5 hundreds = 500, 6 hundreds = 600, 7 hundreds = 700, 8 hundreds = 800 and 9 hundreds = 900. Using a spike abacus and beads of different colours, we represent 999 as shown. 9 blue, 9 green and 9 pink beads on the abacus represent 999. H TO Remove all the beads and Th H T O represent 999 put an orange bead on the represent 1000 next spike. This represents one thousand. We write it as 1000. 1000 is the smallest 4-digit number. Now, we know four places: ones, tens, hundreds and thousands. Let us represent 4732 in the place value chart. Numbers 21 Ascend_G3_Maths_Book_TB_Part1.indb 21 8/3/2023 11:37:23 AM
Thousands (Th) Hundreds (H) Tens (T) Ones (O) The greatest 4-digit 4 7 32 number is 9999. We count by 1000s as 1000 (one thousand), 2000 (two thousand)... till 9000 (nine thousand). Expanded form of 4-digit numbers The form in which a number is written as the sum of the place values of its digits is called its expanded form. Let us now learn to write the expanded form of 4-digit numbers. Example 1: Expand the following numbers. a) 3746 b) 6307 Solution: Write the digits of the given numbers in the place value chart, as shown. Expanded forms: Th H TO a) 3746 = 3000 + 700 + 40 + 6 a) 3 7 46 b) 6307 = 6000 + 300 + 0 + 7 b) 6 3 0 7 Writing number names of 4-digit numbers Observe the expanded form and place value chart for a 4-digit number, 8015. Th H TO 8 0 15 Place values 5 ones = 5 1 tens = 10 0 hundreds = 0 8 thousands = 8000 We can call 8015 as the standard form of the number. Let us look at an example. Example 2: Write the expanded forms and number names of these numbers. a) 1623 b) 3590 Solution: To expand the given numbers, write them in the correct places in the place value chart. 22 Numbers Ascend_G3_Maths_Book_TB_Part1.indb 22 8/3/2023 11:37:23 AM
Expanded forms: Th H T O a) 1623 = 1000 + 600 + 20 + 3 a) 1 6 2 3 b) 3590 = 3000 + 500 + 90 + 0 b) 3 5 9 0 Writing in words (Number names): a) 1623 = One thousand six hundred and twenty-three b) 3590 = Three thousand five hundred and ninety We can write the standard form of a number from its expanded form. Let us see an example. Example 3: Write the standard form of 3000 + 400 + 60 + 5. Solution: Write the numbers in the place value Th H T O chart in the correct places. Write the 3 46 5 digits one beside the other, starting from the thousands place. 3000 + 400 + 60 + 5 = 3465 So, the standard form of 3000 + 400 + 60 + 5 is written as 3465. Train My Brain c) 9385 Write the number names of: a) 2884 b) 4563 3.1 I Apply We can solve a few real-life examples using the knowledge of 4-digit numbers. Example 4: Ram has some money with him as shown. Calculate the amount that Ram has and write it in figures and words. 23 Numbers 8/3/2023 11:37:24 AM Ascend_G3_Maths_Book_TB_Part1.indb 23
Solution: 2 notes of `500 = `1000 1 note of `100 = `100 3 notes of `10 = `30 1 coin of `5 = `5 So, the amount that Ram has = `1000 + `100 + `30 + `5 = `1135 In words, `1135 is one thousand one hundred and thirty-five rupees. Example 5: The number of students in different schools is given in the table. Read the table and answer the questions that follow. Name of schools Number of students Juniper High School 2352 Peony High School 4782 Plumeria High School 7245 Amaryllis High School 9423 Hiptage High School 1281 a) What is the number of students in Plumeria High School? Write the number in words. b) How many students are there in Hiptage High School? Write the number in words. Solution: a) The number of students in Plumeria High School is 7245. In words, it is seven thousand two hundred and forty-five. b) T he number of students in Hiptage High School is 1281. In words, it is one thousand two hundred and eighty-one. A place value chart helps us to form numbers using given digits. Here is an example. Example 6: A number has 6 in the thousands place and 5 in the hundreds place. It has 1 in the tens place and 4 in the ones place. What is the number? Solution: Write the digits in the place value chart according to Th H T O their places as shown. So, the required number is 6514. 6 5 1 4 3.1 I Explore We have learnt the concepts of expanded form and place value chart. Now, we will solve a few examples to identify numbers from the abacus. 24 Numbers Ascend_G3_Maths_Book_TB_Part1.indb 24 8/3/2023 11:37:25 AM
Example 7: Write the numbers represented by these abacuses. a) b) c) Th H T O Th H T O Th H T O Solution: Follow these steps to write the numbers. Step 1: Write the number of beads in each Th H T O Number Step 2: place in the place value chart. a) 1 3 3 2 1332 Put a 0 in the places where there are b) 5 0 3 0 5030 no beads. c) 4 0 3 4 4034 Example 8: Draw beads on the abacus to show the given numbers. a) 3178 b) 6005 c) 4130 Th H T O Solution: Step 1: Follow these steps to show the given numbers. a) 3 1 7 8 Write the digits of the given numbers in the place b) 6 0 0 5 value chart. c) 4 1 3 0 Step 2: Draw the number of beads on each spike of the abacus to show the digit in each place of the number. Th H T O Th H T O Th H T O a) 3178 b) 6005 c) 4130 Drill Time 3.1: Count by Thousands 1) Write the numbers in the place value chart. a) 1451 b) 8311 c) 9810 d) 1000 e) 7613 e) 9819 2) Write the numbers in their expanded forms. a) 8712 b) 6867 c) 1905 d) 4000 Numbers 25 Ascend_G3_Maths_Book_TB_Part1.indb 25 8/3/2023 11:37:25 AM
Drill Time 3) Write the number names of the following numbers: a) 9125 b) 5321 c) 3100 d) 1900 e) 7619 4) Form 4-digit numbers from the following: a) 4 in the thousands place, 3 in the hundreds place, 0 in the tens place and 2 in the ones place b) 9 in the thousands place, 1 in the hundreds place, 4 in the tens place and 0 in the ones place c) 5 in the thousands place, 4 in the hundreds place, 9 in the tens place and 7 in the ones place d) 8 in the thousands place, 2 in the hundreds place, 6 in the tens place and 5 in the ones place e) 1 in the thousands place, 2 in the hundreds place, 3 in the tens place and 4 in the ones place 5) Word problems a) The number of people in different rows in a football stadium is as given: R ow 1: 2345 Row 2: 6298 Row 3: 7918 Row 4: 8917 Row 5: 1118 (A) W hat is the number of people in Row 1? Write the number in words. (B) How many people are there in Row 4? Write the number in words. b) R am has 4 notes of `500, a note of `200, a note of `20 and a coin of `2. How much money does he have? Write the amount in figures and words. 3.2: Compare 4-digit Numbers I Think Farida has 3506 paper clips and her brother has 3605 paper clips. Farida wants to know who has more paper clips. But the numbers appear to be the same, and she is confused. Can you tell who has more number of paper clips? 26 Numbers Ascend_G3_Maths_Book_TB_Part1.indb 26 8/3/2023 11:37:25 AM
3.2 I Recall In class 2, we have learnt to compare 3-digit numbers and 2-digit numbers. Let us quickly revise the concept. A 2-digit number is always greater than a 1-digit number. A 3-digit number is always greater than a 2-digit number and a 1-digit number. So, a number with more number of digits is always greater than a number with lesser digits. We use the symbols >, < or = to compare two numbers. 3.2 I Remember and Understand Comparing two 4-digit numbers is similar to comparing two If two numbers have 3-digit numbers. an equal number of digits, start comparing Let us understand the steps to compare through an example. from the leftmost digit. Example 9: Compare: 5382 and 5380 Solution: Follow these steps to compare the given numbers. Steps Solved Solve this Step 1: Compare the number of digits 5382 and 5380 7469 and 7478 Count the number of digits in the given numbers. The number having more number of digits is Both 5382 and greater. 5380 have 4 digits. Step 2: Compare thousands If two numbers have the same number of digits, 5=5 ____ = ____ compare the thousands digits. The number with the greater digit in the thousands place is 3=3 ____ = ____ greater. Step 3: Compare hundreds If the digits in the thousands place are the same, compare the digits in the hundreds place. The number with the greater digit in the hundreds place is greater. Numbers 27 Ascend_G3_Maths_Book_TB_Part1.indb 27 8/3/2023 11:37:26 AM
Steps Solved Solve this 5382 and 5380 7469 and 7478 Step 4: Compare tens If the digits in the hundreds place are also the 8=8 ____ < ____ same, compare the digits in the tens place. The So, number with the greater digit in the tens place is 2>0 greater. So, ____ < ____ Step 5: Compare ones 5382 > 5380 If the digits in the tens place are also the same, - compare the digits in the ones place. The number with the greater digit in the ones place is greater. When the ones place are the same, the numbers are equal. Note: Once we can decide a greater/smaller number, the steps that follow need not be carried out. Train My Brain Find the greater number in each of the following pairs. a) 7364, 7611 b) 8130, 8124 c) 4371, 4378 3.2 I Apply We can apply the knowledge of comparing numbers and place value to: 1) arrange numbers in the ascending and descending orders. 2) form the greatest and the smallest numbers using the given digits. Ascending and descending orders Ascending Order: The arrangement of numbers from the smallest to the greatest Descending Order: The arrangement of numbers from the greatest to the smallest Example 10: Arrange 4305, 4906, 4005 and 4126 in the ascending and descending orders. 28 Numbers Ascend_G3_Maths_Book_TB_Part1.indb 28 8/3/2023 11:37:26 AM
Solution: Follow these steps to arrange the given numbers in the ascending and descending orders. Step 1: Ascending Order Compare the digits in the thousands place: Step 2: All the numbers have 4 in their thousands place. Compare the digits in the hundreds place: 4005 – 0 hundreds, 4126 –1 hundred, 4305 – 3 hundreds and 4906 – 9 hundreds Step 3: So, 4005 < 4126 < 4305 < 4906. Arranging the numbers in ascending order: 4005, 4126, 4305, 4906 Step 1: Descending Order Compare the digits in the thousands place: Step 2: All the numbers have 4 in their thousands place. Compare the digits in the hundreds place: 4005 – 0 hundreds, 4126 – 1 hundred, 4305 – 3 hundreds and 4906 – 9 hundreds Step 3: So, 4906 > 4305 > 4126 > 4005 Arranging the numbers in descending order: 4906, 4305, 4126, 4005 Simpler way! The descending order of numbers is just the reverse of their ascending order. Forming the greatest and the smallest 4-digits numbers Let us learn to form the greatest and the smallest 4-digit numbers. Look at the following examples. Example 11: Form the greatest and the smallest 4-digit number using 4, 3, 7 and 5 (without repeating the digits). Solution: The given digits are 4, 3, 7 and 5. The steps to find the greatest 4-digit number are given below. Numbers 29 Ascend_G3_Maths_Book_TB_Part1.indb 29 8/3/2023 11:37:26 AM
Step 1: Arrange the digits in descending order as 7 > 5 > 4 > 3. Step 2: Place the digits in the place value chart from left to right. So, the greatest 4-digit number formed is 7543. Th H T O The steps to find the smallest 4-digit number are given 7543 below. Step 1: Arrange the digits in ascending order as Th H T O 3 < 4 < 5 < 7. 34 5 7 Step 2: Place the digits in the place value chart from left to right. So, the smallest 4-digit number formed is 3457. Example 12: Form the smallest 4-digit number using 4, 1, 0 and 6 (without repeating the digits). Solution: The given digits are 4, 1, 0 and 6. Step 1: Arrange the digits in ascending order as 0 < 1 < 4 < 6. Step 2: Place the digits in the place value chart from left to Th H T O right. But the number formed is 0146 or 146. 01 4 6 It is a 3-digit number. In such cases, we interchange the first two digits in Th H T O the place value chart. 10 4 6 So, the smallest 4-digit number formed is 1046. Example 13: Form the smallest and the greatest 4-digit numbers using 4, 0, 8 and 6 (with repeating the digits). Solution: The given digits are 4, 0, 8 and 6. Follow the steps to form the smallest 4-digit number. Step 1: Find the smallest digit. 0 is the smallest of the given digits. (But a number cannot begin with 0.) Step 2: If the smallest digit is ‘0’, find the next smallest digit, which is 4. Write ‘4’ in the thousands place. Write ‘0’ in the rest of the places. Therefore, the smallest 4-digit number is 4000. 30 Numbers Ascend_G3_Maths_Book_TB_Part1.indb 30 8/3/2023 11:37:26 AM
Note: If the smallest of the given digits is not ‘0’, repeat the smallest digit four times to form the smallest number. Now, let us form the largest 4-digit number from the given digits. Step 1: The largest of the given digits is 8. Step 2: Repeat the digit four times to form the largest 4-digit number. Therefore, the largest 4-digit number that can be formed is 8888. 3.2 I Explore Let us see a few real-life examples where we use the comparison of 4-digit numbers. Example 14: 4538 people visited an exhibition on Saturday and 3980 people visited it on Sunday. On which day did fewer people visit the exhibition? Solution: Number of people who visited the exhibition on Saturday = 4538 Number of people who visited the exhibition on Sunday = 3980 Comparing both the numbers using the place value chart, Th H T O Th H T O 4 53 8 3 98 0 4 > 3 or in other words, 3 < 4 So, 3980 < 4538. Therefore, fewer people visited the exhibition on Sunday. Example 15: Razia arranged the numbers 7123, 2789, 2876 and 4200 in the ascending order as 2876, 2789, 4200, 7123. Reena arranged them as 2789, 2876, 4200, 7123. Who arranged them correctly? Why? Solution: Reena’s arrangement is correct. Reason: Comparing the hundreds place of the smaller of the given numbers (that is, 2876 and 2789): 7 hundreds < 8 hundreds. As 2789 < 2876, Reena’s arrangement is correct. Numbers 31 Ascend_G3_Maths_Book_TB_Part1.indb 31 8/3/2023 11:37:26 AM
Drill Time 3.2: Compare 4-digit Numbers 1) Compare the following numbers using <, > or =. a) 8710, 9821 b) 1689, 1000 c) 4100, 4100 d) 2221, 2222 e) 6137, 6237 f) 7091, 7019 2) Arrange the numbers in ascending and descending orders. a) 4109, 5103, 1205, 5420 b) 7611, 7605, 7609, 7610 c) 9996, 8996, 1996, 4996 d) 5234, 6213, 1344, 5161 e) 4234, 6135, 4243, 6524 f) 6512, 1814, 3797, 3893 3) Form the greatest and the smallest 4-digit numbers without repeating the digits. a) 3, 5, 9, 2 b) 1, 5, 9, 4 c) 7, 4, 1, 8 d) 9, 1, 3, 5 e) 8, 2, 3, 4 f) 4, 7, 0, 2 4) Word problems a) 5426 people visited a museum on Friday and 3825 people visited it on the following Sunday. On which day did fewer people visit the museum? b) A shopkeeper sold 1105 milk chocolate bars and 2671 white chocolate bars. Which type of chocolate bars did he sell more? c) M anish trekked a distance of 1851 m on Day 1 and 1815 m on Day 2. On which day did he trek more distance? Maths Munchies I am a 4-digit number. The digit in my thousands place is the same as that in my ones place. The digit in my ones place is 5. The digits in my tens place and hundreds place are the same. The digit in my hundreds place is 3 less than the digit in my thousands place. Who am I? 32 Numbers Ascend_G3_Maths_Book_TB_Part1.indb 32 8/3/2023 11:37:27 AM
Connect the Dots Social Studies Fun Without the concept of thousands, we would have never been able to estimate the heights of the tallest mountain peaks in the world! Take a look at the tallest peaks across each continent. English Fun There are two kinds of sounds – vowels and consonants. Underline all the vowels in the given words. a) HUNDRED b) THOUSAND c) DIGITS A Note to Parent Play a new dice game with your child. Each player rolls the dice four times in a row and writes the numbers from left to right. The winner is the one who gets the smallest number in one round. Play multiple rounds until your child understands the concepts of place value and comparison of 4-digit numbers. Numbers 33 Ascend_G3_Maths_Book_TB_Part1.indb 33 8/3/2023 11:37:28 AM
4 Addition I Will Learn estimating the sum of two numbers About rounding off numbers to the nearest tens adding numbers with and without regrouping adding two numbers mentally 4.1: Estimate the Sum of Two Numbers You have learnt how to add 2-digit and 3-digit numbers. However, we don’t always need to know the exact sum of numbers. We can try to simply estimate the sum at times. What is estimation? When we ‘estimate’ something, we use words such as ‘around’ or ‘about’. For example, when we say there are about 50 students in a class, we mean that the number is close to 50. The actual number could be 49 or 51 or 54 or even 45! When we estimate numbers, we usually round them off. Rounding off numbers makes them easier to use. People estimate numbers by rounding them off in their day-to-day lives. What is rounding off? Rounding off is nothing but estimation. Estimating the actual number to its nearby number is called rounding off. We usually round off numbers to their nearest tens. Look at these examples. 86 is rounded off to 90. 23 is rounded off to 20. 64 is rounded off to 60. 34 Ascend_G3_Maths_Book_TB_Part1.indb 34 8/3/2023 11:37:29 AM
Can you say why? Discuss with a partner. If the digit in the ones place is 4 or less, you round off the number down to the previous tens. And, if the digit is 5 or more, you round it off to the next tens. Do you want to see how we round off numbers on a number line? Suppose Rita has 61 boxes. Now, she wants to round it off to the nearest tens. How will she do it? 61 lies between 60 and 70 (multiples of 10). 61 is closer to 60 thanE7s0t.imation of Sum To round off to the So, we can mWakeecan estiimmaattee athnedssuamy thoaf thReitagihvaesnanbuomutb6e0rsbboyxes. nearest tens, observe the digit in the ones rounding them off to the nearest tens, hundreds and place. Howtdhoouwseanedstsimpalatecethaes sruemquoirfetdw.o numbers? • If the digit in the Now that youTkonothwe wnheaart erostutnedninsg off is, you can use the same method to ones place is 0, 1, the sum of twEoxnaummpbleer1s as well. estim2a, t3eor 4, the digit is changed to ‘0’, keeping the other digits the same. • If the digit in the TO TO ones place is 5, 6, 60 7, 8 or 9, add 1 to 1 the tens digit and 63 +3 0 +2 8 change the ones digit to 0. 90 91 Note how theTehsetimesatitmedatseudmsius mveriys cclloossee ttoo tthhee aaccttuuaall ssuumm.of the two numbenTreosa.rroeustnhduonfdf rtoedths,e Imagine thaTt yootuhehanveear2e2spt ehnusntdordeidstsribute among your friends. observe the digit in the What will youExroaumnpdleof2f 22 to? tens place. • If the digit in the Now imagineEsthtiamt aytoeutrhteeascuhmerogfiv3e4s3yaonud2567m5otoretpheennse. aWrehsatthwuilnl ydorueds. tens place is 0, 1, 2, round off 26 to? Estimated sum Actual sum 3 or 4, change both HTO the tens and the rounded off andH26 wTill bOe. ones digits to 0, Find out wha3t4t3heneeasttriomestatht1ee0d0ssum3o0f022 3 0 0 1 keeping the other 343 digit3s5the same. Addition rounded up + 6 0 0 +5 7 5 • If the digit in the tens place is 5, 6, 575Ascend_G3_Maths_Book_TB_Part1.indb 35 to the 600 900 918 78,/38/202o3 r119:37,:3a0 AdMd 1 to
C an you think of a similar sum using two 3-digit numbers? Try estimating the sum with a partner. Work on it and share it with the class. Hint: 3-digit numbers have to be rounded off to the nearest 100. Round off 256 to the nearest 100s. If the digit in the tens place is greater than 100 150 200 250 300 350 400 or equal to 5, round up the number to the 256 next hundreds. Far Near 256 is nearer to 300 than 200. So, it is rounded up to 300. Reflection Time! 1) How does rounding off make calculations easier? 2) Why is estimating useful? 3) Can you think of any real-life situation in which you can round off and estimate the sum of 2-digit and 3-digit numbers? Drill Time 4.1: Estimate the Sum of Two Numbers Ro1u)n dEosftfim43a5te8 ttohethseunmeaorfetshte10fo00llos.wing: a) 21 and 15 b) 49 and 12 c) 85 and 90 3 000 d) 22420a00n43d58 5245 000 e)6060702 and 189 If the digit in fth) e325 and 416 hundreds place is less than 5, round 2) Word pNroeabrleFmars off the number to the 435 8 isan)eSauresar tnoh4a0s0046thraend5r0o0s0e.s and Mukeshsahmaes t2h2ouysealnlodws. roses. Estimate the So, it is rotuontadel nduomffbtoer4o00f 0ro. ses. b) Rakesh has 67 pencils and Mona has 43 pencils. Estimate the number of Example 7pencils both of them have in all. Round off 7620 to the nearest 1000s. 36 7000 7620 8000 9000 If the digit in the Addition hundreds 6000 8/3/2023 11:37:31 AM place is greater than 5, Far NearAscend_G3_Maths_Book_TB_Part1.indb 36 round up the number to the next thousands.
4.2: Add 3-digit and 4-digit Numbers I Think Farida’s father bought her a shirt for `335 and a skirt for `806. Farida wants to find how much her father had spent in all. How do you think she can find that? 4.2 I Recall We can add 2-digit or 3-digit numbers by writing them one below the other. This method of addition is called vertical addition. Let us revise the earlier concept and solve the following. a) 22 + 31 = _________ b) 42 + 52 = _________ c) 82 + 11 = _________ d) 101 + 111 = _________ e) 100 + 200 = _________ f) 122 + 132 = _________ 4.2 I Remember and Understand Let us now understand the addition of two 3-digit numbers with While adding, regrouping. We will also learn to add two 4-digit numbers. regroup if the Add 3-digit numbers with regrouping sum of the digits is more than 9. Sometimes, the sum of the digits in a place is more than 9. In such cases, we need to regroup the sum. We then carry forward the digit to the next place. Example 1: Add 245 and 578. Solution: Arrange the numbers one below the other. Regroup if necessary. Addition 37 Ascend_G3_Maths_Book_TB_Part1.indb 37 8/3/2023 11:37:31 AM
Step 1: Add the ones. Solved Step 3: Add the Step 2: Add the tens. hundreds. H TO H TO 1 H TO 11 11 245 245 245 +578 +578 +578 823 3 23 Th H T O Th H T O Solve these Th H T O 171 823 + 219 + 197 390 + 121 Add 4-digit numbers without regrouping Adding two 4-digit numbers is similar to adding two 3-digit numbers. Let us understand this through an example. Example 2: Add 1352 and 3603. Solution: Arrange the numbers one below the other. Solved Step 1: Add the ones. Step 2: Add the tens. Th H T O Th H T O 135 2 135 2 +3 6 0 3 +3 6 0 3 5 55 Step 3: Add the hundreds. Step 4: Add the thousands. Th H T O Th H T O 135 2 135 2 +3 6 0 3 +3 6 0 3 495 5 955 38 Addition Ascend_G3_Maths_Book_TB_Part1.indb 38 8/3/2023 11:37:31 AM
Th H T O Solve these Th H T O 419 0 111 1 +2 0 0 0 Th H T O +2 2 2 2 200 2 +3 0 0 3 Add 4-digit numbers with regrouping We regroup the sum when it is equal to or more than 10. Example 3: Add 1456 and 1546. Solution: Arrange the numbers one below the other. Add and regroup, if necessary. Solved Step 1: Add the ones. Step 2: Add the tens. Th H T O Th H T O 1 11 1456 1456 +1 5 4 6 +1 5 4 6 2 02 Step 3: Add the hundreds. Step 4: Add the thousands. Th H T O 111 Th H T O 1456 111 1456 +1 5 4 6 +1 5 4 6 002 3002 Th H T O Solve these O Th H T O Th H T 175 8 267 8 459 2 +5 6 6 2 +1 3 3 2 +1 4 5 6 Addition 39 Ascend_G3_Maths_Book_TB_Part1.indb 39 8/3/2023 11:37:32 AM
Train My Brain c) 8837 + 1040 Solve: a) 321 + 579 b) 725 + 215 4.2 I Apply Look at a few examples where we use addition of 3-digit and 4-digit numbers. Example 4: Vinod had some stamps out of which he gave 278 stamps to his brother. Vinod now has 536 stamps left with him. How many stamps did he have in the beginning? H TO Solution: Number of stamps Vinod has now = 536 11 Number of stamps he gave his brother = 278 5 36 Number of stamps Vinod had in the +2 78 beginning = 536 + 278 = 814 8 14 Therefore, Vinod had 814 stamps in the beginning. Example 5: Ajit collected `2683 and Radhika collected `3790 for donating to a nursing home. What is the total money collected? Solution: Amount collected by Ajit = `2683 Th H T O Amount collected by Radhika = `3790 11 Total amount collected for the donation 2 6 83 = `2683 + `3790 = `6473 +3 7 9 0 Example 6: The number of Class 3 students in Heena’s 6 4 73 school is 236. The number of Class 3 students in Veena’s school is 289. Solution: How many total number of students are present in + H TO Class 3 of both the schools? 1 1 2 36 Number of students in Heena’s school = 236 2 89 Number of students present in Veena’s school = 289 Total number of students present in Class 3 of both 5 25 the schools = 236 + 289 = 525 4.2 I Explore Addition Let us see a few more examples on the addition of 4-digit numbers. 8/3/2023 11:37:32 AM 40 Ascend_G3_Maths_Book_TB_Part1.indb 40
Example 7: Three pieces of ribbon of lengths 2134 cm, 1185 cm and 3207 cm were cut from a long piece of ribbon. What was the total length of the ribbon before the pieces were cut? Th H T O Solution: The pieces of ribbon are 2134 cm, 1185 cm 11 and 3207 cm long. 2134 Length of the ribbon before the pieces were + 1 1 8 5 cut = 2134 cm + 1185 cm + 3207 cm Therefore, the ribbon was 6526 cm long before + 3 2 0 7 6526 the pieces were cut. Example 8: Payal, Eesha and Suma have 1284, 7523 and 5215 stamps respectively. Frame an addition problem. Solution: An addition problem contains words such as - in all, total, altogether and so on. So, the question can be ‘‘Payal, Eesha and Suma have 1284, 7523 and 5215 stamps respectively. How many stamps do they have altogether?” Drill Time 4.2: Add 3-digit and 4-digit Numbers 1) Add 3-digit numbers with regrouping. a) 481 + 129 b) 119 + 291 c) 288 + 288 d) 346 + 260 e) 690 + 110 f) 584 + 329 2) Add 4-digit numbers without regrouping. a) 1234 + 1234 b) 1000 + 2000 c) 4110 + 1332 d) 5281 + 1110 e) 7100 +1190 f) 1403 + 2563 3) Add 4-digit numbers with regrouping. a) 5671 + 1430 b) 3478 + 2811 c) 4356 + 1753 d) 2765 + 1342 e) 4901 + 2222 f) 7625 + 1648 4) Word problems a) There are 142 people in Train A and 469 people in Train B. How many people are riding in both the trains altogether? b) A li scores 272 points in one level of a computer game. His friend, Jenny, scores 538 points in the next level. What is their total score for both the levels? Addition 41 Ascend_G3_Maths_Book_TB_Part1.indb 41 8/3/2023 11:37:32 AM
4.3: Add 2-digit Numbers Mentally We have already learnt to add two 1-digit numbers mentally. Let us now learn to add two 2-digit numbers mentally through these examples. How do we add 2-digit numbers mentally? Whenever we add two 2-digit numbers mentally, we first add the digits of the numbers separately. You can follow the steps given below to mentally add 2-digit numbers. Look at the solved example of mentally adding 29 and 56 as well. Steps Adding 29 and 56 Add 83 and 47 29 = 20 + 9 83 = ___ + ____ Step 1: Regroup the two given 56 = 50 + 6 47 = ___ + ____ numbers as tens and ones 9 + 6 = 15 ____ + ____ = ____ mentally. 20 + 50 = 70 ____ + ____ = ____ Step 2: Add the digits in the ones place of the two 70 + 15 ____ + ___ = ____ numbers mentally. = 70 + 10 + 5 = 85 So, 83 + 47 = ___. Step 3: Add the digits in the So, 29 + 56 = 85. tens place of the two numbers mentally. Step 4: Add the sums from steps 2 and 3 mentally (regroup if needed). Step 5: Write the sum of the given numbers. Solve the following mentally. a) 21 + 30 b) 42 + 57 c) 42 + 98 Suraj has 34 sheets of paper, while Kamal has 27. How many sheets of paper do they have in all? Solve mentally. Vivek has 49 bags and Shyam has 29 bags. How many bags do they have in total? Solve mentally. 42 Addition Ascend_G3_Maths_Book_TB_Part1.indb 42 8/3/2023 11:37:33 AM
Reflection Time! 1) Name some games where you add numbers mentally. 2) Imagine you have accompanied your mother to the local fruit shop. Your mother bought apples for `40 and oranges for `33. She gave the shopkeeper a `100 note. The shopkeeper gave her back `23. Estimate mentally if she got back the correct change. Drill Time 4.3: Add 2-digit Numbers Mentally 1) Add 2-digit numbers mentally with regrouping. a) 45 and 47 b) 25 and 56 c) 12 and 19 d) 27 and 35 e) 17 and 37 f) 49 and 26 2) Add 2-digit numbers mentally without regrouping. a) 31 and 22 b) 22 and 42 c) 45 and 51 d) 11 and 34 e) 32 and 61 f) 54 and 13 Addition 43 Ascend_G3_Maths_Book_TB_Part1.indb 43 8/3/2023 11:37:34 AM
Drill Time 3) Solve the word problems mentally. a) Suraj has 51 red marbles and 64 blue marbles. How many marbles does he have in all? b) Ram has `35 and his friend has `72. How much money do they have in total? c) Hari has 77 candies and his sister has 33 candies. How many candies do they have in total? d) Parul has 53 stamps and Sonu has 65 stamps. How many stamps do they have in all? e) There are 36 chalk pieces in box 1 and 45 chalk pieces in box 2. How many chalk pieces are there in total? Maths Munchies Steps to estimate the sum of 2-digit numbers mentally: Step 1: Take any two numbers, say 75 and 12. Add the tens digit which gives 8. Step 2: Count the digits in the ones place. Among the two numbers, only 75 has a digit in the ones place that is equal to 5. Step 3: A dd this count to the tens place. So, the sum in the tens place be- comes 9. Place ‘0‘ in the ones place. So, the estimated sum is 90. 44 Addition Ascend_G3_Maths_Book_TB_Part1.indb 44 8/3/2023 11:37:34 AM
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