Open 4 fingers on one hand. Open 3 fingers on the other. B egin counting the fingers on one hand. Continue to count the fingers on the other hand. The number counted for the last finger is the sum or total. So, 4 + 3 = 7. b) 1 + 5 + = So, 1 + 5 = 6. c) 5 + 5 += So, 5 + 5 = 10. Addition using the number line A line marked with numbers is called the number line. We use it to add numbers. Let us see an example. Example 3: Add using the number line: a) 2 and 3 b) 4 and 4 c) 3 and 4 Solution: a) L et us find 2 + 3 using the number line. Draw an arrow from 0 to 2. Addition 47
T o add 3 to 2, we move 3 steps to the right of 2. Draw arrows for each step as shown. The number at which the steps end is 5. So, 2 + 3 = 5. b) 4 + 4 So, 4 + 4 = 8. c) 3 + 4 So, 3 + 4 = 7. Vertical or column addition We can add numbers by writing them one below the other. This is called vertical addition or column addition. Let us see a few examples. Addition of 1-digit numbers Example 4: Add 6 and 2 by writing the numbers in columns. Solution: Write the numbers under the ones place, as shown. O 6 +2 8 48
Addition of 2-digit numbers Example 5: Add the following by writing the numbers in columns. 23 + 32 Solution: Step 1: Add the ones Step 2: Add the tens TO TO 23 23 +32 +32 5 55 Solve these TO TO TO 41 14 78 +2 8 +3 3 +2 1 ? Train My Brain Add the following: a) 3 + 7 (Using fingers) b) 6 + 5 (Using a number line) c) 15 +14 (Using vertical addition) I Apply We now know how to add numbers. Let us see some real-life examples of addition of numbers. Example 6: Madhu has 5 kites and Sita has 4 kites. How many kites do they have in all? Addition 49
Solution: Write the numbers one below the other. Add them and write the sum as shown. O 5 +4 9 So, Madhu and Sita have 9 kites in all. Example 7: Ram had 14 marbles. Shyam gave him 15 marbles. How many marbles does Ram have altogether? Solution: Write the numbers one below the other. Add TO them and write the sum as shown. So, Ram has 29 marbles altogether. 14 + 15 29 I Explore (H.O.T.S.) We have learnt how to add two 1-digit and 2-digit numbers. Let us now learn to add three 1-digit and 2-digit numbers. Example 8: Sunita bought 2 mangoes, 3 apples and 4 bananas. How many fruits did she buy altogether? Solution: Write the numbers under the ones place and add. O 2 +3 +4 9 So, Sunita bought 9 fruits. 50
Example 9: There are 14 students in Row 1. Row 2 has 15 students. Row 3 has 10 students. How many students are there altogether? Solution: Write the numbers one below the other. Step 1: Add the ones Step 2: Add the tens T O T O 14 14 + 15 + 15 + 10 + 10 9 39 So, there are 39 students altogether. Maths Munchies We can add two numbers by drawing lines. 5+3=8 Suppose we have to add 5 and 3. First, draw 5 lines and then 3 lines as shown. Then count the lines continuously. The number we get for the last line is the sum of 5 and 3. 5 + 3 = │││││ + │││ = 8. So, 5 + 3 = 8. Connect the Dots EVS Fun How many fingers do we have in all? To find this, we ‘add’ the number of fingers of our two hands. Now, count the number of fingers of your two hands. Addition 51
English Fun Sometimes, we add two words to make a single meaningful word. For example, Moon + light = Moonlight Sun + rays = Sunrays Can you write a few more such words? Drill Time 4.1 Add 1-digit Numbers and 2-digit Numbers 1) Add these numbers using the number line. a) 3 and 3 b) 2 and 6 c) 1 and 7 d) 4 and 2 e) 3 and 4 2) Add these numbers using the vertical or column method. a) 2 and 5 b) 3 and 6 c) 21 and 42 d) 17 and 61 e) 10 and 40 3) Word problems a) I have 2 pens and my sister has 2 pens. What is the total number of pens with us? b) K rish picked 12 sticks and Sanjay picked 20 sticks. How many sticks did they pick in all? A Note to Parent Play snakes and ladders with your child. Make him or her add the numbers and move the coins. This will help him or her to understand addition in a fun way. 52
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