Page 48 - Viva

Exercise 3.5

1. Solve the following.

(a) 846 + 12 – 320 (b) 38 + 746 + 98 – 138
(c) 365 + 268 – 342 (d) 182 + 764 – 498

2. Solve the following word problems.

(a) There were 450 kites in a shop. In the first week 150 kites were sold and in the
second week 92 kites were sold. How many kites were left in the shop?

(b) There are 42 horses, 81 cows and 36 dogs on a farm. If 14 cows and 17 horses
are shifted to a new farm, how many animals are left on the old farm?
(c) A showroom has 329 bedsheets. If 79 more bedsheets are added to the stock
and 261 bedsheets are sold, how many bedsheets are left in the showroom?

Subtraction of 2-Digit Numbers Mentally

Method 1: Break the subtrahend into tens and ones. Then subtract the tens from the
minuend. Finally, subtract the ones from the difference obtained.

Example 14: Subtract 45 from 76. Example 15: Subtract 28 from 97.
Solution: 45 = 40 + 5 Solution: 28 = 20 + 8
76 – 40 = 36 97 – 20 = 77

36 – 5 = 31 77 – 8 = 69

So, 76 – 45 = 31. So, 97 – 28 = 69.
Method 2: Find the number to be added to the subtrahend to get the minuend by counting
forward. This method works if the two numbers are close to each other.

Example 16: Subtract 88 from 91. Example 17: Subtract 53 from 59.
Solution: 88 + 3 = 91 Solution: 53 + 6 = 59

So, 91 – 88 = 3. So, 59 – 53 = 6.
Method 3: Round off the subtrahend to the nearest 10. Subtract the two numbers and
then correct the difference.

Example 18: Subtract 38 from 73.
Solution: Round off 38 to 40. (40 – 38 = 2)

Subtract 40 from 73.
73 – 40 = 33

As we subtracted 2 more than 38, correct the answer by adding 2 to 33.
So, 73 – 38 = 35.

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