Page 115 - Start Up Mathematics_1

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Addition and Subtraction

Now, you know about numbers upto 99. You also know that 10 is the smallest
2-digit number and 99 is the biggest 2-digit number. Now let’s see how we can
add and subtract 2-digit numbers.

Addition of 2-Digit and 1-Digit Numbers

Look at the given example. Common Mistake!

Tens Ones Step 1: Add the ones and Always write the numbers
in their correct place.
2 3 write the sum under
ones. 3 0
+ 4
3 + 4 = 7 + 4

2 7 Step 2: Write the tens as it is. 7 0 ()

1 Add the numbers.

Tens Ones Tens Ones Tens Ones Tens Ones

(a) 6 2 (b) 5 1 (c) 3 3 (d) 7 0

+ 3 + 7 + 4 + 6

Tens Ones Tens Ones Tens Ones Tens Ones
(e) 4 2 (f) 8 3 (g) 1 5 (h) 2 2

+ 5 + 1 + 3 + 7

Tens Ones Tens Ones Tens Ones Tens Ones
(i) 3 4 (j) 2 6 (k) 4 2 (l) 9 2

+ 2 + 3 + 7 + 6

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