Last updated at June 15, 2018 by Teachoo

Transcript

Ex 1.3, 2 Give a rough estimate (by rounding off to nearest hundreds) & also a closer estimate (by rounding off to nearest tens) : Make four more such examples. (a) 439 + 334 + 4317439 + 334 + 4317 Rounding off to nearest tens 439 is rounded off to 440 334 is rounded off to 330 4317 is rounded off to 4320 So, Estimated sum = 440 + 330 + 4320 = 4320 + 440 + 330 ∴ Estimated sum = 5,090 Rounding off to nearest hundreds 439 is rounded off to 400 334 is rounded off to 300 4317 is rounded off to 4300 So, Estimated sum = 400 + 300 + 4300 ∴ Estimated sum = 5,000 Ex 1.3, 2 Give a rough estimate (by rounding off to nearest hundreds) & also a closer estimate (by rounding off to nearest tens) : Make four more such examples. (b) 1,08,734 – 47,5991,08,734 – 47,599 Rounding off to nearest tens 1,08,734 is rounded off to 1,08,730 47,599 is rounded off to 47,600 So, Estimated answer = 1,08,730 − 47,600 ∴ Estimated answer = 61,130 Rounding off to nearest hundreds 1,08,734 is rounded off to 1,08,700 47,599 is rounded off to 47,600 So, Estimated answer = 1,08,730 − 47,600 ∴ Estimated answer = 61,100 Ex 1.3, 2 Give a rough estimate (by rounding off to nearest hundreds) & also a closer estimate (by rounding off to nearest tens) : Make four more such examples. (c) 8325 – 4918325 – 491 Rounding off to nearest tens, 8325 is rounded off to 8330 491 is rounded off to 490 So, Estimated answer = 8330 − 490 ∴ Estimated answer = 7,840 Rounding off to nearest hundreds 8325 is rounded off to 8300 491 is rounded off to 500 So, Estimated answer = 8300 − 500 ∴ Estimated answer = 7800 Ex 1.3, 2 Give a rough estimate (by rounding off to nearest hundreds) & also a closer estimate (by rounding off to nearest tens) : Make four more such examples. (d) 4,89,348 – 48,3654,89,348 – 48,365 Rounding off to nearest tens 4,89,348 is rounded off to 4,89,350 48,365 is rounded off to 48,370 So, Estimated answer = 4,89,350 − 48,370 ∴ Estimated answer = 4,40,980 Rounding off to nearest hundreds 4,89,348 is rounded off to 4,89,300 48,365 is rounded off to 48,400 So, Estimated answer = 4,89,300 − 48,400 ∴ Estimated answer = 4,40,900

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.