Page 135 - New Medley 3 Semester 1
P. 135
4. Simplify: 5132 + 3120 – 2196
+ –
Ans:
Estimating Difference
A zoo was visited by 5628 people in first week. The number of visitors
increased to 7908 in second week. Let us estimate the increase in number
of visitors by rounding to nearest tens.
7908 rounds to 7910 7 9 1 0
5628 rounds to 5630 – 5 6 3 0
2 2 8 0
7908 – 5628 ≈ 7910 – 5630 = 2280
The zoo had nearly 2280 more visitors in the second week.
We can also estimate the difference by rounding to nearest hundreds and
thousands.
Example 7: Estimate 5896 – 3902 by rounding to nearest hundreds.
Solution: Rounding off to hundreds
5896 rounds to 5 9 0 0
3902 rounds to – 3 9 0 0
Estimated difference 2 0 0 0
Example 8: Estimate 8953 – 3105 by rounding to nearest thousands.
Solution: Rounding off to thousands
8953 rounds to 9 0 0 0
3105 rounds to – 3 0 0 0
Estimated difference 6 0 0 0
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