Give a rough estimate (by rounding off to nearest hundreds) and also a closer estimate (by rounding off to nearest tens):

(i) 439 + 334 + 4317

(ii) 8325 - 491

(iii) 1,08,734 - 47,599

(iv) 4,89,348 - 48,365

(i) 439 + 334 + 4317

Rough estimate (nearest hundreds):

439 → 400 (tens digit 3 < 5)

334 → 300 (tens digit 3 < 5)

4317 → 4300 (tens digit 1 < 5)

Estimated sum = 400 + 300 + 4300 = 5,000.

Closer estimate (nearest tens):

439 → 440 (ones digit 9 > 5)

334 → 330 (ones digit 4 < 5)

4317 → 4320 (ones digit 7 > 5)

Estimated sum = 440 + 330 + 4320 = 5,090.

Hence, the rough estimate is 5,000 and the closer estimate is 5,090.

(ii) 8325 - 491

Rough estimate (nearest hundreds):

8325 → 8300 (tens digit 2 < 5)

491 → 500 (tens digit 9 > 5)

Estimated difference = 8300 - 500 = 7,800.

Closer estimate (nearest tens):

8325 → 8330 (ones digit 5)

491 → 490 (ones digit 1 < 5)

Estimated difference = 8330 - 490 = 7,840.

Hence, the rough estimate is 7,800 and the closer estimate is 7,840.

(iii) 1,08,734 - 47,599

Rough estimate (nearest hundreds):

1,08,734 → 1,08,700 (tens digit 3 < 5)

47,599 → 47,600 (tens digit 9 > 5)

Estimated difference = 1,08,700 - 47,600 = 61,100.

Closer estimate (nearest tens):

1,08,734 → 1,08,730 (ones digit 4 < 5)

47,599 → 47,600 (ones digit 9 > 5)

Estimated difference = 1,08,730 - 47,600 = 61,130.

Hence, the rough estimate is 61,100 and the closer estimate is 61,130.

(iv) 4,89,348 - 48,365

Rough estimate (nearest hundreds):

4,89,348 → 4,89,300 (tens digit 4 < 5)

48,365 → 48,400 (tens digit 6 > 5)

Estimated difference = 4,89,300 - 48,400 = 4,40,900.

Closer estimate (nearest tens):

4,89,348 → 4,89,350 (ones digit 8 > 5)

48,365 → 48,370 (ones digit 5)

Estimated difference = 4,89,350 - 48,370 = 4,40,980.

Hence, the rough estimate is 4,40,900 and the closer estimate is 4,40,980.