RS Aggarwal Solutions: Number System (Exercise 1D) | Mathematics (Maths) Class 6 PDF Download

Q.1. Round each of the following numbers to the nearest ten :
(a) 36
(b) 173
(c) 3869

(d) 16378
Ans. (a) 40
(b) 170
(c) 3870
(d) 16380

Q.2. Round each of the following numbers to the nearest hundred :
(a) 814
(b) 1254
(c) 43126
(d) 98165
Ans.
(a) 800
(b) 1300
(c) 43100
(d) 98200

Q.3. Round each of the following numbers tothe nearest thousand :
(a) 793

(b) 4826
(c) 16719
(d) 28394
Ans.
(a) 1000
(b) 5000
(c) 17000
(d) 28000

Q. 4. Round each of the following numbers to the nearest ten thousand :
(a) 17514
(b) 26340
(c) 34890

(d) 272685
Ans.
(a) 20000
(b) 30000
(c) 30000
(d) 270000

Estimate each sum to the nearest ten :
Q.5. (57 + 34)
Ans.
(57 + 34)
57 estimated to the nearest ten = 60
34 estimated to the nearest ten = 30
Required sum = 60 + 30 = 90

Q.6. (43 + 78)
Ans.
(43 + 78)
43 estimated to the nearest ten = 40
78 estimated to the narest ten = 80
Required sum = 40 + 80 = 120 Ans.

Q.7. (14 + 69).
Ans.
(14 + 69)

14 estimated to the nearest ten = 10
69 estimated to the nearest ten = 70
Required sum = 10 + 70 = 80 Ans.

Q.8. (86 + 19).

Ans.
(86 + 19)

86 estimated to the nearest ten = 90

19 estimated to the nearest ten = 20

Required sum = 90 + 20 = 110 Ans.

Q.9. (95 + 58).
Ans.
(95 + 58)
95 estimated to the nearest ten = 100
58 estimated to the nearest ten = 60
∴ Required sum = 100 + 60 = 160

Q.10. (77 + 63).

Ans.
77 estimated to the nearest ten = 80

63 estimated to the nearest ten = 60
∴ Required sum = 80 + 60 = 140

Q.11. (356 + 275).
Ans.
(356 + 275)
356 estimated to the nearest ten = 360
275 estimated to the nearest ten = 280
∴ Required sum = 360 + 280 = 640

Q.12. (463 + 182).
Ans. 463 + 182
463 estimated to the nearest ten = 460
182 estimated to the nearest ten = 180
∴ Required sum = 460 + 180 = 640

Q.13. (538 + 276).
Ans. (538 + 276)
538 estimated to the nearest ten = 540
276 estimated to the nearest ten = 280
Required sum = 540 + 280 = 820

Estimate each sum to the nearest hundred :
Q.14. (236 + 689).
Ans.
(236 + 689)
236 estimated to the nearest hundred = 200
689 estimated to the nearest hundred = 700
∴ Required sum = 200 + 700 = 900

Q.15. (458 + 324).
Ans. (458 + 324)
458 estimated to the nearest hundred = 500
324 estimated to the nearest hundred = 300
∴ Required sum = 500 + 300 = 800

Q.16. (170 + 395).
Ans. (170 + 395)
170 estimated to the nearest hundred = 200
395 estimated to the nearest hundred = 400
∴ Required sum = 200 + 400 = 600

Q.17. (3280 + 4395).
Ans. (3280 + 4395)
3280 estimated to the nearest hundred = 3300
4395 estimated to the nearest hundred = 4400
∴ Required sum = 3300 + 4400
= 7700

Q.18. (5130 + 1410).
Ans. (5130 + 1410)
5130 estimated to the nearest hundred = 5100
1410 estimated to the nearest hundred = 1400
∴ Required sum = 5100 + 1400 = 6500

Q.19. (5130 + 1410).
Ans. (5130 + 1410)
5130 estimated to the nearest hundred = 5100
1410 estimated to the nearest hundred = 1400
∴ Required sum = 5100 + 1400 = 6500

Q.19. (10083 + 29380).
Ans. (10083 + 29380)
10083 estimated to the nearest hundred = 10100

29380 estimated to the nearest hundred = 29400
∴ Required sum = 10100 + 29400 = 39500

Estimate each sum to the nearest thousand :
Q.20. (32836 + 16466).
Ans. (32836 + 16466)
32836 estimated to the nearest thousand = 33000
16466 estimated to the nearest thousand = 16000
∴ Required sum = 33000 + 16000 = 49000

Q.21. (46703 + 11375).
Ans. (46703 + 11375)
46703 estimated to the nearest thousand = 47000
11375 estimated to the nearest thousand = 11000
∴ Required sum = 47000 + 11000 = 58000

Q. 22. There are 54 balls in box A and 79 balls in box B. Estimate the total number of balls in both the boxes taken together.
Ans. 54 balls + 79 balls
54 balls estimated to the nearest 10 = 50
79 balls estimated to the nearest 10 = 80
∴ Required total number of balls
= 50 + 80 + 130

Estimate each difference to the nearest ten :
Q.23. (53 – 18).
Ans.. (53 – 18)
53 estimated to the nearest ten = 50
18 estimated to the nearest ten = 20
∴ Difference of 50 and 20 = 50 – 20 = 30

Q.24. (97 – 38).
Ans. (97 – 38)
97 estimated to the nearest ten = 100
38 estimated to the nearest ten = 40
∴ Difference of 100 and 40 = 100 – 40 = 60

Q. 25. (409 – 148).
Ans. (409 – 148)
409 estimated to the nearest ten = 410
148 estimated to the nearest ten = 150
∴ Difference of 410 and 150 = 410 – 150
= 260

Estimate each difference to the nearest hundred :
Q.26. (678 – 215).
Ans. (678 – 215)
678 estimated to the nearest hundred = 700

215 estimated to the nearest hundred = 200
∴ Difference between 700 and 200
= 700 – 200 = 500

Q.27. (957 – 578).
Ans. (957 – 578)

957 estimated to the nearest hundred = 1000
578 estimated to the nearest hundred = 600
∴ Difference between 1000 and 600
= 1000 – 600 = 400

Q.28. (7258 – 2429).
Ans. (7258 – 2429)
7258 estimated to the nearest hundred = 7300
2429 estimated to the nearest hundred = 2400
∴ Difference between 7300 and 2400
= 7300 – 2400 = 4900

Q.29. (5612 – 3095)
Ans.
5612 estimated to the nearest hundred = 5600
3095 estimated to the nearest hundred = 3100
∴ Difference between 5600 and 3100
= 5600 – 3100 = 2500

Estimate each difference to the nearest thousand:
Q.30. (35863 – 27677)
Ans.
35863 estimated to the nearest thousand = 36000
27677 estimated to the nearest thousand = 28000
∴ Difference between 36000 and 28000
= 36000 – 28000 = 8000

Q.31. (47005 – 39488).
Ans. (47005 – 39488)
47005 estimated to the nearest thousand = 47000

39488 estimated to the nearest thousand = 39000
Difference between 47000 and 39000
= 47000 – 39000 = 8000
15 estimated to the nearest ten = 20
34 estimated to the nearest ten = 30
20 × 30 = 600 Ans.