These NCERT Solutions for Class 6 Maths Chapter 1 Knowing Our Numbers Ex 1.3 Questions and Answers are prepared by our highly skilled subject experts.
NCERT Solutions for Class 6 Maths Chapter 1 Knowing Our Numbers Exercise 1.3
Question 1.
Estimate each of the following using general rule:
(a) 730 + 998
(b) 796-314
(c) 12,904 + 2,888
(d) 28,292-21,496
Make ten more such examples of addition, subtraction and estimation of their outcome.
Answer:
(a) 730 round off to 700
998 round off to 1000
Estimated sum = 1700
(b) 796 round off to 800
314 round off to 300
Estimated sum = 500
(c) 12904 round off to 13000
2888 round off to 3000
Estimated sum = 16000
(d) 28292 round off to 28000
21496 round off to 21000
Estimated difference = 7000
Question 2.
Give a rough estimate (by rounding off to nearest hundreds) and also a closer estimate (by rounding off to nearest tens):
(a) 439 + 334 + 4317
(b) 1,08,737-47,599
(c) 8325 – 491
(d) 4,89,348-48,365
Make four more such examples
Answer:
(a) Rounding off to nearest hundreds
439 round off to 400
334 round off to 300
4,317 round off to 4,300
Estimated sum = 5,000
Again, Rounding off to nearest tens
439 → 440
334 → 330
4,317 → 4,320
∴ Closer estimate = 440 + 330 + 4,320 = 5,090
(b) Rounding off to Areas tens
= 440 + 330 + 4320 = 5090
108737 round off to 108700
47599 round off to 47600
Estimated difference = 61100
Again, Rounding off to nearest tens
1,08,734 → 1,08,730
47,599 → 47,600
∴ Closer estimate=1,08,730 – 47,600 = 61,130
(c) Rounding off to nearest tens
= 108730-47600 = 61130
8325 round off to 8300
491 round off to 500
Estimated difference = 7800
Again, Rounding off to nearest tens
8,325 → 8,330
491 → 490
∴ Closer estimate = 8,330 – 490 = 7,800
(d) Rounding off to nearest tens
= 8330 – 490 = 7840
489348 round off to 489300
48365 round off to 48400
Estimated difference = 440900
Again, Rounding off to nearest tens
4,89,348→ 4,89,300
48,365 → 48,370
Closer estimate=4,89,350-48,370=4,40,980
Question 3.
Estimate the following products using general rule:
(a) 578 x 161
(b) 5281 x 3491
(c) 1291 x 592
(d) 9250 x 29
Make four more such examples
Answer:
(a) 578 x 161
578 round off to 600
161 round off to 200
The estimated product
= 600 x 200 = 1,20,000
(b) 5281 x 3491
5281 round of to 5,000
3491 round off to 3,500
The estimated product
= 5,000 x 3,500 = 1,75,00,000
(c) 1291 x 592
1291 round off to 1300
592 round off to 600
The estimated product
= 1300 x 600 = 7,80,000
(d) 9250 x 29
9250 round off to 10,000
29 round off to 30
The estimated product
= 10,000 x 30 = 3,00,000