Estimation of numbers with its illustrations is the main concept discussed under Exercise 2(B) of Selina Solutions Concise Mathematics Class 6 Chapter 2 Estimation. Our subject experts have solved these solutions with the intention to help students in solving the problems with ease. Students who fail to grasp during class hours are suggested to practice these solutions in-depth for better understanding. These solutions are the best study materials for students who aspire to score good marks in the examination. Students can make use of the PDF of Selina Solutions Concise Mathematics Class 6 Chapter 2 Estimation Exercise 2(B) and download free, from the links given below.
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Access Selina Solutions Concise Mathematics Class 6 Chapter 2: Estimation Exercise 2(B)
Exercise 2(b) page no: 17
1.Estimate the sum of each pair of numbers to the nearest ten :
(i) 67 and 44
(ii) 34 and 87
(iii) 23 and 66
(iv) 78 and 18
(v) 96 and 55
Solution:
(i) 67 to the nearest ten is 70
44 to the nearest ten is 40
Sum of these numbers = 70 + 40
= 110
∴Required sum = 110
(ii) 34 to the nearest ten is 30
87 to the nearest ten is 90
Sum of these numbers = 30 + 90
= 120
∴Required sum = 120
(iii) 23 to the nearest ten is 20
66 to the nearest ten is 70
Sum of these numbers = 20 + 70
= 90
∴Required sum = 90
(iv) 78 to the nearest ten is 80
18 to the nearest ten is 20
Sum of these numbers = 80 + 20
= 100
∴Required sum = 100
(v) 96 to the nearest ten is 100
55 to the nearest ten is 60
Sum of these numbers = 100 + 60
= 160
∴Required sum = 160
2.Estimate the sum of each pair of numbers to the nearest hundred:
(i) 336 and 782
(ii) 546 and 342
(iii) 270 and 495
(iv) 4280 and 5295
(v) 4230 and 2410
Solution:
(i) 336 to the nearest hundred is 300 and 782 to the nearest hundred is 800
Sum of these numbers = (300 + 800)
= 1100
∴Required sum = 1100
(ii) 546 to the nearest hundred is 500 and 342 to the nearest hundred is 300
Sum of these numbers = (500 + 300)
= 800
∴Required sum = 800
(iii) 270 to the nearest hundred is 300 and 495 to the nearest hundred is 500
Sum of these numbers = (300 + 500)
= 800
∴Required sum = 800
(iv) 4280 to the nearest hundred is 4300 and 5295 to the nearest hundred is 5300
Sum of these numbers = (4300 + 5300)
= 9600
∴Required sum = 9600
(v) 4230 to the nearest hundred is 4200 and 2410 to the nearest hundred is 2400
Sum of these numbers = (4200 + 2400)
= 6600
∴Required sum = 6600
3.Estimate the sum of the following pair of numbers to the nearest thousand:
(i) 53826 and 36455
(ii) 56802 and 22475
Solution:
(i) 53826 to the nearest thousand is 54000
36455 to the nearest thousand is 36000
∴Required sum = 54000 + 36000
= 90000
(ii) 56802 to the nearest thousand is 57000
22475 to the nearest thousand is 22000
∴Required sum = 57000 + 22000
= 79000
4. Estimate the following differences correct to nearest ten :
(i) 82 – 27
(ii) 96 – 36
(iii) 508 – 248
Solution:
(i) 82 to the nearest ten is 80 and 27 to the nearest ten is 30
∴Required difference = (80 – 30)
= 50
(ii) 96 to the nearest ten is 100 and 36 to the nearest ten is 40
∴Required difference = (100 – 40)
= 60
(iii) 508 to the nearest ten is 510 and 248 to the nearest ten is 250
∴Required difference = (510 – 250)
= 260
5.Estimate each difference to the nearest hundred:
(i) 769 – 314
(ii) 856 – 687
(iii) 6352 – 2086
Solution:
(i) 769 to the nearest hundred = 800 and
314 to the nearest hundred = 300
∴Required difference = (800 – 300)
= 500
(ii) 856 to the nearest hundred = 900 and
687 to the nearest hundred = 700
∴Required difference = (900 – 700)
= 200
(iii) 6352 to the nearest hundred = 6400 and
2086 to the nearest hundred = 2100
∴Required difference = (6400 – 2100)
= 4300
6.Estimate each difference to the nearest thousand:
(i) 45974 – 38766
(ii) 76003 – 48399
Solution:
(i) 45974 to the nearest thousand = 46000
38766 to the nearest thousand = 39000
∴Required difference = (46000 – 39000)
= 7000
(ii) 76003 to the nearest thousand = 76000
48399 to the nearest thousand = 48000
∴Required difference = (76000 – 48000)
= 28000
7. Estimate each of the following products by rounding off each number to the nearest ten :
(i) 49 x 52
(ii) 63 x 38
(iii) 27 x 54
(iv) 53 x 85
(v) 74 x 67
Solution:
(i) 49 to the nearest ten = 50 and
52 to the nearest ten = 50
∴Required product = (50 × 50)
= 2500
(ii) 63 to the nearest ten = 60 and
38 to the nearest ten = 40
∴Required product = (60 × 40)
= 2400
(iii) 27 to the nearest ten = 30 and
54 to the nearest ten = 50
∴Required product = (30 × 50)
= 1500
(iv) 53 to the nearest ten = 50 and
85 to the nearest ten = 90
∴Required product = (50 × 90)
= 4500
(v) 74 to the nearest ten = 70 and
67 to the nearest ten = 70
∴Required product = (70 × 70)
= 4900
8. Estimate each of the following products by rounding off each number to the nearest hundred :
(i) 477 x 213
(ii) 624 x 236
(iii) 333 x 247
(iv) 537 x 283
(v) 382 x 127
Solution:
(i) 477 x 213
477 to the nearest hundred = 500 and
213 to the nearest hundred = 200
∴Required product = (500 × 200)
= 100000
(ii) 624 x 236
624 to the nearest hundred = 600 and
236 to the nearest hundred = 200
∴Required product = (600 × 200)
= 120000
(iii) 333 x 247
333 to the nearest hundred = 300 and
247 to the nearest hundred = 200
∴Required product = (300 × 200)
= 60000
(iv) 537 x 283
537 to the nearest hundred = 500 and
283 to the nearest hundred = 300
∴Required product = (500 × 300)
= 150000
(v) 382 x 127
382 to the nearest hundred = 400 and
127 to the nearest hundred = 100
∴Required product = (400 × 100)
= 40000
9. Estimate each of the following products by rounding off the first number correct to nearest ten and the other number correct to nearest hundred :
(i) 28 x 287
(ii) 432 x 128
(iii) 48 x 165
(iv) 72 x 258
(v) 83 x 664
Solution:
(i) 28 x 287
28 to the nearest ten = 30 and
287 to the nearest hundred = 300
∴Required product = (30 × 300)
= 9000
(ii) 432 x 128
432 to the nearest ten = 430 and
128 to the nearest hundred = 100
∴Required product = (430 × 100)
= 43000
(iii) 48 x 165
48 to the nearest ten = 50 and
165 to the nearest hundred = 200
∴Required product = (50 × 200)
= 10000
(iv) 72 x 258
72 to the nearest ten = 70 and
258 to the nearest hundred = 300
∴Required product = (70 × 300)
= 21000
(v) 83 x 664
83 to the nearest ten = 80 and
664 to the nearest hundred = 700
∴Required product = (80 × 700)
= 56000
10. Estimate each of the following quotients by converting each number to the nearest ten:
(i) 87 ÷ 28
(ii) 84 ÷ 23
(iii) 77 ÷ 22
(iv) 198 ÷ 24
(v) 355 ÷ 26
Solution:
(i) 87 ÷ 28
87 ÷ 28 is approximately (to the nearest 10) equal to
90 ÷ 30 = 3
(ii) 84 ÷ 23
84 ÷ 23 is approximately (to the nearest 10) equal to
80 ÷ 20 = 4
(iii) 77 ÷ 22
77 ÷ 22 is approximately (to the nearest 10) equal to
80 ÷ 20 = 4
(iv) 198 ÷ 24
198 ÷ 24 is approximately (to the nearest 10) equal to
200 ÷ 20 = 10
(v) 355 ÷ 26
355 ÷ 26 is approximately (to the nearest 10) equal to
360 ÷ 30 = 12
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