Page 132 - New Medley 4 Semester 1

EXERCISE 2.3

Fill in the blanks.

1. 17252 + 67258 = + 17252

2. 37725 + = 52728 + 37725

3. + 314227 = + 241419

4. 21091 + = 32742 +

5. [29552 + 41758] + 74041 = 29552 + [41758 + ]

6. [445074 + 676072] + 457075 = + [ + 457075]

7. [12707 + ] + 31565 = + [22164 + ]

8. 96952 + 0 =

9. + 0 = 872274

10. + 62585 = 62585

Estimating Sum

Mr. Jhon visits an electronics showroom. He wants to buy a laptop and a
camera. The laptop is listed at ` 28,741 and a camera is listed at ` 16,582. He

decides to buy both. He decides to pay by using his credit card. He wishes to

estimate the total price he has to pay so that he can check if his credit card
has that much balance or not.

Many a times we don’t need the exact sum but just a round about idea

of what the sum could be. This is called finding an estimate.

We round the numbers to the nearest tens, hundreds, thousands or ten
thousands depending upon the accuracy we want. We now add these

rounded figures to get an estimate.

Example 6: Estimate 24954 + 34778 by rounding to the nearest tens.

Solution: Rounding off to tens

24954 rounds to 2 4 9 5 0

34778 rounds to + 3 4 7 8 0

Estimated sum 5 9 7 3 0

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