Give a rough estimate (by rounding of to nearest hundreds) and also a closer estimate (by rounding of to nearest tens):
a) 439 + 334 + 4,317

b) 1,08,734 - 47,599

c) 8325 - 491

d) 4,89,348 - 48,365

Solution:

a) 439 + 334 + 4,317

Rounding off 439 to the nearest hundreds, we get 400. Rounding off 334 to the nearest hundreds, we get 300. And, rounding off 4,317 to the nearest hundreds, we get 4,300.

Therefore, 400 + 300 + 4,300 = 5,000

It means that answer is equal to 5,000 when we round off different terms to the nearest hundreds.

Rounding off 439 to the nearest tens, we get 440 Rounding off 334 to the nearest tens, we get 330 And, rounding off 4,317 to the nearest tens, we get 4,320

Therefore, 440 + 330 + 4,320 = 5,090 It means that answer is equal to 5,090 when we round off different terms to the nearest tens.

b) 1,08,734 - 47,599

Rounding off 1,08,734 to the nearest hundreds, we get 1,08,700 And rounding off 47,599 to the nearest hundreds, we get 47,600

Therefore, 1,08,700-47,600=61,100

It means that answer is equal to 61,100 when we round off the terms to the nearest hundreds. Rounding off 1,08,734 to the nearest tens, we get 1,08,730 And rounding off 47,599 to the nearest tens, we get 47,600.

Therefore, 1,08,730-47,600=61,130 It means that answer is equal to 61,130 when we round off terms to the nearest tens.

c) 8325 - 491

Rounding off 8,325 to the nearest hundreds, we get 8,300 And, rounding off 491 to the nearest hundreds, we get 500 Therefore, 8,300-500=7,800

It means that answer is equal to 7,800 when we round off terms to the nearest hundreds. Rounding off 8,325 to the nearest tens, we get 8,330 And, rounding off 491 to the nearest tens, we get 490

Therefore, 8,330-490=7,840 It means that answer is equal to 7,840 when we round off terms to the nearest tens.

d) 4,89,348 - 48,365 

Rounding off 4,89,348 to the nearest hundreds, we get 4,89,300 And, rounding off 48,365 to the nearest hundreds, we get 48,400

Therefore, 4,89,300-48,400=4,40,900

It means that answer is equal to 4,40,900 when we round off terms to the nearest hundreds. Rounding off 4,89,348 to the nearest tens, we get 4,89,350 And, rounding off 48,365 to the nearest tens, we get 48,370

Therefore, 4,89,350-48,370=4,40,980 It means that answer is equal to 4,40,980 when we round off terms to the nearest tens.

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Updated on: 10-Oct-2022

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