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SAI International School

Sub – Mathematics

Class - IV

Topic – Operations

Sub-topic: Estimating Operations

 Introduction – We use estimation to make out calculation easier.

**Estimation means “Rounding Off”

 Estimating Sum: We round off the addends and then find out the sum.
e.g. 1: find the sum of 2345 and 9872 after rounding off them to the nearest
100.
Solution:
Step 1: round off 2345 to the nearest 100.
2345 2300
Step 2: round off 9872 to the nearest 100.
9872 9900
Step 3: add the rounded off value.
2300 + 9900 = 12200

 Estimating Difference: We round off the minuend and subtrahend, then
subtract the numbers.
e.g. 1: find the difference between 32908 and 12453 after rounding off them to
the nearest 1000.
Solution:
Step 1: round off 32908 to the nearest 1000.
32908 33000
Step 2: round off 12453 to the nearest 1000.
12453 12000
Step 3: subtract the rounded off value.
33000 – 12000 = 21000
 Estimating Product: We round off the multiplier and the multiplicand and then
multiply the numbers.
e.g. 1: Estimate the product of 543 and 876.

Solution:
**Here, we have to round off both the numbers to nearest 100 as it will be easier
to get the product.