Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions

Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals)

Selina Publishers Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals)

Decimal Fractions Exercise 4A – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
Convert the following into fractions in their lowest terms :
(i) 3.75
(ii) 0.5
(iii) 2.04
(iv) 0.65
(v) 2.405
(vi) 0.085
(vii) 8.025
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4A 1
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4A 300

Question 2.
Convert into decimal fractions
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4A Q2
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4A 2

Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4A 3

Question 3.
Write the number of decimal places in :
(i) 0.4762
(ii) 7.00349
(iii) 8235.403
(iv) 35.4
(v) 2.608
(vi) 0.000879
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4A 4

Question 4.
Write the following decimals as word statements :
(i) 0.4,0.9,0.1
(ii) 1.9, 4.4, 7.5
(iii) 0.02, 0.56, 13.06
(iv) 0.005,0.207, 111.519
(v) 0.8, 0.08, 0.008, 0.0008
(vi)256.1, 10.22, 0.634
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4A 5

Question 5.
Convert the given fractions into like fractions:
(i) 0.5,3.62,43.987 and 232.0037
(ii) 215.78, 33.0006, 530.3 and 0.03569
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4A 6

Decimal Fractions Exercise 4B – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
Add:
(i) 0.5 and 0.37 (ii) 3.8 and 8.7
(iii) 0.02, 0.008 and 0.309
(iv) 0. 4136, 0. 3195 and 0.52
(v) 9.25, 3.4 and 6.666
(vi) 3.007, 0.587 and 18.341
(vii) 0.2, 0.02 and 2.0002
(viii) 6. 08, 60.8, 0.608 and 0.0608
(ix) 29.03, 0.0003, 0.3 and 7.2
(x) 3.4, 2.025, 9.36 and 3.6221
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 7
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 8
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 9

Question 2.
Subtract the first! number from the second :
(i) 5.4, 9.8
(ii) 0.16, 4.3
(iii) 0.82, 8.6
(v) 2.237, 9.425
(vi) 41 .03, 59.46
(vii) 3.92. 26.86
(viii) 4.73, 8.5
(ix) 12.63, 36.2
(x) 0.845, 3.71
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 10
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 11
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 12

Question 3.
Simplify :
(i) 28.796 -13.42 – 2.555
(ii) 93.354 – 62.82 – 13.045
(iii) 36 – 18.59 – 3.2
(iv) 86 + 16.95 – 3.0042
(v) 32.8 – 13 – 10.725 +3.517
(vi) 4000 – 30.51 – 753.101 – 69.43
(vii) 0.1835 + 163.2005 – 25.9 – 100
(viii) 38.00 – 30 + 200.200 – 0.230
(ix) 555.555 + 55.555 – 5.55 – 0.555
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 13
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 14
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 15
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 16

Question 4.
Find the difference between 6.85 and 0.685.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 17

Question 5.
Take out the sum of 19.38 and 56.025 then subtract it from 200. 111.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 18

Question 6.
Add 13.95 and 1.003 ; and from the result, subtract the sum of 2.794 and 6.2.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 19

Question 7.
What should be added to 39.587 to give 80.375 ?
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 20

Question 8.
What should be subtracted from 100 to give 19.29?
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 21

Question 9.
What is the excess of 584.29 over 213.95 ?
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 22

Question 10.
Evaluate:
(i) (5.4 – 0.8) + (2.97 -1.462)
(ii) (6.25 + 0.36) -(17.2 – 8.97)
(iii) 9.004 + (3 -2.462)
(iv) 879.4 – (87.94 – 8 .794)
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 23

Question 11.
What is the excess of 75 over 48.29?
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 24

Question 12.
If A = 237.98 and B = 83.47.
Find :
(i) A – B
(ii) B – A.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 25

Question 13.
The cost of one kg of sugar increases from ?28.47 to T32.65. Find the increase in cost.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4B 26

Decimal Fractions Exercise 4C – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
Multiply:
(i) 0.87 by 10
(ii) 2.948 by 100
(iii) 6.4 by 1000
(iv) 5.8 by 4
(v) 16.32 by 28
(vi) 5. 037 by 8
(vi) 4.6 by 2.1
(viii) 0.568 by 6.4
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 27

Question 2.
Multiply each number by 10, 100, 1000 :
(i) 0.5
(ii) 0.112
(iii) 4.8
(iv) 0.0359
(v) 16.27
(vi) 234.8
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 28
Question 3.
Evaluate:
(i) 5.897 x 2.3
(ii) 0.894 x 87
(iii) 0.01 x 0.001
(iv) 0.84 x 2.2 x 4
(v) 4.75 x 0.08 x 3
(vi) 2.4 x 3.5 x 4.8
(vii) 0.8 x 1.2 x 0.25
(viii) 0.3 x 0.03 x 0.003
(ix) 12.003 x (0.2)5
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 29
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 30
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 31

Question 4.
Divide :
(i) 54.9 by 10
(ii) 7.8 by 100
(iii) 324.76 by 1000
(iv) 12.8 by 4
(v) 27.918 by 9
(vi) 4.672 by 8
(vii) 4.32 by 1.2
(viii) 7.644 by 1.4
(ix) 4.8432 by 0.08
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 32
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 33
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 34

Question 5.
Divide each of the given numbers by 10, 100, 1000 and 10000
(i) 2.1
(ii) 8.64
(iii) 5-01
(iv) 0.0906
(v) 0.125
(vi) 111.11
(vii) 0.848 x 3
(viii)4.906 x (0.2) ²
(ix) (1.2)² x(0.9)²
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 35
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 36
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 37
Question 6.
Evaluate :
(i) 9.75 + 5
(ii) 4.4064 + 4
(iii) 27.69 + 30
(iv) 19.25 + 25
(v) 20.64+ 16
(vi) 3.204 + 9
(vii) 0.125 + 25
(viii) 0.14616 + 72
(ix) 0.6227+ 1300
(x) 257.894+ 0-169
(xi) 6.3 + (0.3)²
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 38
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 39
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 40
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 41
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 42

Question 7.
Evaluate:
(i) 4.3 x 0.52 x 0.3
(ii) 3.2 x 2.5 x 0.7
(iii) 0.8 x 1.5 x 0.6
(iv) 0.3 x 0.3 x 0.3
(v) 1.2 x 1.2 x 0.4
(vi) 0.4 x 0.04 x 0.004
(vii) 0.5 x 0.6 x 0.7
(Viii) 0.5 x 0.06 x 0.007
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 43
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 44
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 45
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 46
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 47
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 48

Question 8.
Evaluate:
(i) (0.9)²
(ii) (0.6)² x 0.5
(iii) 0.3 x (0.5)²
(iv) (0.4)³
(v) (0.2)3 x 5
(vi) (0.2)3 x 0.05
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 49
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 50

 Question 9.
Find the cost of 36.75 kg wheat at the rate of ₹12.80 per kg.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 51

Question 10.
The cost of a pen is ₹56.15. Find the cost of 16 such pens.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 52

Question 11.
Evaluate:
(i) 0.0072 ÷ 0.06
(ii) 0.621 ÷ 0.3
(iii) 0.0532 ÷ 0.005
(iv) 0.01162 ÷ 0.14
(v) (7.5 x 40.4) ÷ 25
(vi) 2.1 ÷ (0.1 x 0.1)
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 53
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 54

Question 12.
Fifteen indentical articles weigh 31.50 kg. Find the weight of each article.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 55

Question 13.
The product of two numbers is 211.2. If one of these two numbers is 16.5, find the other number.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 56

Question 14.
One dozen identical articles cost ₹45.96. Find the cost of each article.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4C 57

Decimal Fractions Exercise 4D – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
Find whether the given division forms a terminating decimal or a non-terminating decimal:
(i) 3 ÷ 8
(ii)8 ÷ 3
(iii) 6÷ 5
(iv) 5 ÷ 6
(v) 12.5 ÷ 4
(vi) 23 ÷ 0.7
(vii) 42 ÷ 9
(viii) 0.56÷ 0.11
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 58
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 59
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 60
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 61
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 62

Question 2.
Express as recurring decimals :
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D Q2

Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 63
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 64
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 65
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 66
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 67
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 68
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 69

Question 3.
Convert into vulgar fraction :
(i) 0.\(\bar { 3 }\)
(ii) 0.\(\bar { 8 }\)
(iii) 4.\(\bar { 4 }\)
(iv) 23.\(\bar { 7 }\)
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 70

Question 4.
Convert into vulgar fraction :
(i) 0.\(\bar { 35 }\)
(ii) 2.\(\bar { 23 }\)
(iii) 1.\(\bar { 28 }\)
(iv) 5.\(\bar { 234 }\)
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 71

Question 5.
Convert into vulgar fraction :
(i) 0 0.3\(\bar { 7 }\)
(ii) 0.2\(\bar { 45 }\)
(iii) 0.68\(\bar { 5 }\)
(iv) 0.4\(\bar { 42 }\)
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4D 72

Decimal Fractions Exercise 4E – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
Round off:
(i) 0 .07, 0.112, 3.59, 9.489 to the nearest tenths.
(ii) 0.627, 100.479, 0 065 and 0.024 to the nearest hundredths.
(iii) 4.83,0.86,451 .943 and 9.08 to the nearest whole number.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4E 73

Question 2.
Simplify, and write your answers correct to the nearest hundredths :
(i) 18 .35 x 1.2
(ii) 62.89 x 0.02
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4E 74

Question 3.
Write the number of significant figures (digits) in:
(i) 35.06
(ii) 0.35
(iii) 7.0068
(iv) 19 .0
(v) 0.0062
(vi) 0 4.2 x 0.6
(vii) 0.08 x 25
(viii) 3.6 ÷ 0.12 .
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4E 75

Question 4.
Write :
(i) 35.869,0 008426,4.952 and 382.7, correct lo three significant figures.
(ii) 60.974. 2.8753, 0.001789 and 400.04, correct to four significant figures.
(iii) 14.29462, 19.2, 46356.82 and 69, correct to five significant figures.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4E 76

Decimal Fractions Exercise 4F – Selina Concise Mathematics Class 7 ICSE Solutions

Question 1.
The weight of an object is 3 .06 kg. Find the total weight of 48 similar objects.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4F 77

Question 2.
Find die cost of 17.5 m cloth at the rate of Rs. 112.50 per metre.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4F 78

Question 3.
One kilogramme of oil costs Rs. 73.40. Find the cost of 9.75 kilogramme of the oil.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4F 79

Question 4.
Total weight of 8 identical objects is 51.2 kg. Find the weight of each object.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4F 80

Question 5.
18.5 m of cloth costs Rs. 666. Find the cost of 3.8 m cloth.
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4F 81
Question 6.
Find die value of:
(i) 0.5 of Rs. 7.60 + 1.62 of Rs. 30
(ii) 2.3 of 7.3 kg + 0.9 of 0.48 kg
(iii) 6.25 of 8.4 – 4.7 of 3.24
(iv) 0.98 of 235 – 0 .09 of 3.2
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4F 82
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4F 83

Question 7.
Evaluate:
(i) 5.6 – 1 .5 of 3.4
(ii) 4.8 ÷ 0.04 of 5
(iii) 0.72 of 80 + 0.2
(iv) 0.72 ÷ 80 of 0.2
(v) 6.45 + (3.9 – 1.75)
(vi) 0.12 of(0.104 – 0.02)+ 0.36 x 0.5
Solution:
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4F 84
Selina Concise Mathematics Class 7 ICSE Solutions Chapter 4 Decimal Fractions (Decimals) Ex 4F 85

Selina Concise Mathematics Class 7 ICSE Solutions

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