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E:\Working\Focus_Learning\Math_Genius_3_(11-09-2024)\Open_Files\CHAP_02
\ 12-Sep-2024 Surender Prajapati Proof-4 Reader’s Sign _______________________ Date __________

example 1: Find the actual sum and the estimated sum by rounding off the numbers to
the nearest 10.

(a) 46 + 72 (b) 312 + 194
Solution:

(a) Actual Sum Estimated Sum (b) Actual Sum Estimated Sum

H t O H t O H t O H t O

1 1 1 1
4 6 rounded up 5 0 3 1 2 rounded down 3 1 0
+ 7 2 rounded down + 7 0 + 1 9 4 rounded down + 1 9 0
1 1 8 1 2 0 5 0 6 5 0 0

example 2: Atul bought a chocolate for `149 and a packet of biscuits for `35. Estimate the
amount he spent by rounding off the numbers to the nearest 10. Is the total estimated

amount more or less than the actual amount?
Solution: Actual Sum Estimated Sum

H t O H t O

1 The estimated sum is more
1 4 9 rounded up 1 5 0 than the actual sum.
+ 3 5 rounded up + 4 0
1 8 4 1 9 0

practice time 2g

Find the actual and the estimated sum by rounding off the numbers to the nearest 10.
Compare the actual and the estimated sum and fill <, > or = in the given blank space.

1. 2.
t O H t O t O H t O

3 4 round off 2 2 round off
+ 6 5 round off + + 8 7 round off +

Actual Sum__________Estimated Sum Actual Sum__________Estimated Sum

3. t O H t O 4. t O H t O

4 6 round off 2 5 round off
+ 3 7 round off + + 6 9 round off +

Actual Sum__________Estimated Sum Actual Sum__________Estimated Sum

44 Mathematics-3