Mathematics
Estimate the following products by rounding off each of its factors nearest to its greatest place:
(i) 578 × 161
(ii) 9650 × 27
Answer
(i) 578 × 161
Rounding off 578 to its greatest place (hundreds): tens digit is 7 (≥ 5), so 578 → 600.
Rounding off 161 to its greatest place (hundreds): tens digit is 6 (≥ 5), so 161 → 200.
Estimated product = 600 × 200 = 1,20,000.
Hence, the estimated product = 1,20,000.
(ii) 9650 × 27
Rounding off 9650 to its greatest place (thousands): hundreds digit is 6 (≥ 5), so 9650 → 10,000.
Rounding off 27 to its greatest place (tens): ones digit is 7 (≥ 5), so 27 → 30.
Estimated product = 10,000 × 30 = 3,00,000.
Hence, the estimated product = 3,00,000.
Related Questions
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
Estimate each of the following by rounding off each number nearest to its greatest place:
(i) 730 + 998
(ii) 5,290 + 17,986
(iii) 796 - 314
(iv) 28,292 - 21,496
Estimate the following products by rounding off each of its factors nearest to its hundreds:
(i) 5281 × 3491
(ii) 1387 × 888
Estimate the following quotients by rounding off each number to its nearest tens:
(i) 423 ÷ 29
(ii) 777 ÷ 27