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Page 1 Exercise 7.4 page: 7.4 1. Express the following fractions as decimals: (i) 23/10 (ii) 139/100 (iii) 4375/1000 (iv) 12 1/2 (v) 75 1/4 (vi) 25 1/8 (vii) 18 3/24 (viii) 39 7/35 (ix) 15 1/25 (x) 111/250 Solution: (i) 23/10 It can be written as = 20 + 3/10 We get = 20/10 + 3/10 By addition = 2 + 3/10 So we get = 2.3 (ii) 139/100 It can be written as = 100 + 30 + 9/100 We get = 100/100 + 30/100 + 9/100 By addition = 1 + 3/10 + 9/100 So we get = 1.39 (iii) 4375/1000 It can be written as = 4000 + 300 + 70 + 5/1000 We get = 4000/1000 + 300/1000 + 70/1000 + 5/1000 By addition = 4 + 3/10 + 7/100 + 5/1000 So we get = 4.375 (iv) 12 1/2 It can be written as = 12 + 1/2 Multiplying and dividing by 5 to get denominator as 10 Page 2 Exercise 7.4 page: 7.4 1. Express the following fractions as decimals: (i) 23/10 (ii) 139/100 (iii) 4375/1000 (iv) 12 1/2 (v) 75 1/4 (vi) 25 1/8 (vii) 18 3/24 (viii) 39 7/35 (ix) 15 1/25 (x) 111/250 Solution: (i) 23/10 It can be written as = 20 + 3/10 We get = 20/10 + 3/10 By addition = 2 + 3/10 So we get = 2.3 (ii) 139/100 It can be written as = 100 + 30 + 9/100 We get = 100/100 + 30/100 + 9/100 By addition = 1 + 3/10 + 9/100 So we get = 1.39 (iii) 4375/1000 It can be written as = 4000 + 300 + 70 + 5/1000 We get = 4000/1000 + 300/1000 + 70/1000 + 5/1000 By addition = 4 + 3/10 + 7/100 + 5/1000 So we get = 4.375 (iv) 12 1/2 It can be written as = 12 + 1/2 Multiplying and dividing by 5 to get denominator as 10 = 12 + [(1/2) × (5/5)] On further calculation = 12 + 5/10 So we get = 12.5 (v) 75 1/4 It can be written as = 75 + 1/4 Multiplying and dividing by 25 to get 100 as denominator = 75 + [(1/4) × (25/25)] On further calculation = 75 + 25/100 By addition = 75.25 (vi) 25 1/8 It can be written as = 25 + 1/8 Multiplying and dividing by 125 to get 1000 as denominator = 25 + [(1/8) × (125/125)] On further calculation = 25 + 125/1000 By addition = 25.125 (vii) 18 3/24 It can be written as = 18 + 3/24 We get = 18 + 1/8 Multiplying and dividing by 125 to get 1000 as denominator = 18 + [(1/8) × (125/125)] On further calculation = 18 + 125/1000 By addition = 18.125 (viii) 39 7/35 It can be written as = 39 + 7/35 We get = 39 + 1/5 Multiplying and dividing by 2 to get 10 as denominator = 39 + [(1/5) × (2/2)] On further calculation = 39 + 2/10 By addition = 39.2 Page 3 Exercise 7.4 page: 7.4 1. Express the following fractions as decimals: (i) 23/10 (ii) 139/100 (iii) 4375/1000 (iv) 12 1/2 (v) 75 1/4 (vi) 25 1/8 (vii) 18 3/24 (viii) 39 7/35 (ix) 15 1/25 (x) 111/250 Solution: (i) 23/10 It can be written as = 20 + 3/10 We get = 20/10 + 3/10 By addition = 2 + 3/10 So we get = 2.3 (ii) 139/100 It can be written as = 100 + 30 + 9/100 We get = 100/100 + 30/100 + 9/100 By addition = 1 + 3/10 + 9/100 So we get = 1.39 (iii) 4375/1000 It can be written as = 4000 + 300 + 70 + 5/1000 We get = 4000/1000 + 300/1000 + 70/1000 + 5/1000 By addition = 4 + 3/10 + 7/100 + 5/1000 So we get = 4.375 (iv) 12 1/2 It can be written as = 12 + 1/2 Multiplying and dividing by 5 to get denominator as 10 = 12 + [(1/2) × (5/5)] On further calculation = 12 + 5/10 So we get = 12.5 (v) 75 1/4 It can be written as = 75 + 1/4 Multiplying and dividing by 25 to get 100 as denominator = 75 + [(1/4) × (25/25)] On further calculation = 75 + 25/100 By addition = 75.25 (vi) 25 1/8 It can be written as = 25 + 1/8 Multiplying and dividing by 125 to get 1000 as denominator = 25 + [(1/8) × (125/125)] On further calculation = 25 + 125/1000 By addition = 25.125 (vii) 18 3/24 It can be written as = 18 + 3/24 We get = 18 + 1/8 Multiplying and dividing by 125 to get 1000 as denominator = 18 + [(1/8) × (125/125)] On further calculation = 18 + 125/1000 By addition = 18.125 (viii) 39 7/35 It can be written as = 39 + 7/35 We get = 39 + 1/5 Multiplying and dividing by 2 to get 10 as denominator = 39 + [(1/5) × (2/2)] On further calculation = 39 + 2/10 By addition = 39.2 (ix) 15 1/25 It can be written as = 15 + 1/25 Multiplying and dividing by 4 to get 100 as denominator = 15 + [(1/25) × (4/4)] On further calculation = 15 + 4/100 By addition = 15.04 (x) 111/250 It can be written as = 111 × [(1/250) × (4/4)] On further calculation = 444/1000 By division = 0.444 2. Express the following decimals as fractions in the lowest form: (i) 0.5 (ii) 2.5 (iii) 0.60 (iv) 0.18 (v) 5.25 (vi) 7.125 (vii) 15.004 (viii) 20.375 (ix) 600.75 (x) 59.48 Solution: (i) 0.5 It can be written as = 5/10 By division = 1/2 (ii) 2.5 It can be written as = 25/10 By division = 5/2 (iii) 0.60 It can be written as = 60/100 By division = 3/5 (iv) 0.18 Page 4 Exercise 7.4 page: 7.4 1. Express the following fractions as decimals: (i) 23/10 (ii) 139/100 (iii) 4375/1000 (iv) 12 1/2 (v) 75 1/4 (vi) 25 1/8 (vii) 18 3/24 (viii) 39 7/35 (ix) 15 1/25 (x) 111/250 Solution: (i) 23/10 It can be written as = 20 + 3/10 We get = 20/10 + 3/10 By addition = 2 + 3/10 So we get = 2.3 (ii) 139/100 It can be written as = 100 + 30 + 9/100 We get = 100/100 + 30/100 + 9/100 By addition = 1 + 3/10 + 9/100 So we get = 1.39 (iii) 4375/1000 It can be written as = 4000 + 300 + 70 + 5/1000 We get = 4000/1000 + 300/1000 + 70/1000 + 5/1000 By addition = 4 + 3/10 + 7/100 + 5/1000 So we get = 4.375 (iv) 12 1/2 It can be written as = 12 + 1/2 Multiplying and dividing by 5 to get denominator as 10 = 12 + [(1/2) × (5/5)] On further calculation = 12 + 5/10 So we get = 12.5 (v) 75 1/4 It can be written as = 75 + 1/4 Multiplying and dividing by 25 to get 100 as denominator = 75 + [(1/4) × (25/25)] On further calculation = 75 + 25/100 By addition = 75.25 (vi) 25 1/8 It can be written as = 25 + 1/8 Multiplying and dividing by 125 to get 1000 as denominator = 25 + [(1/8) × (125/125)] On further calculation = 25 + 125/1000 By addition = 25.125 (vii) 18 3/24 It can be written as = 18 + 3/24 We get = 18 + 1/8 Multiplying and dividing by 125 to get 1000 as denominator = 18 + [(1/8) × (125/125)] On further calculation = 18 + 125/1000 By addition = 18.125 (viii) 39 7/35 It can be written as = 39 + 7/35 We get = 39 + 1/5 Multiplying and dividing by 2 to get 10 as denominator = 39 + [(1/5) × (2/2)] On further calculation = 39 + 2/10 By addition = 39.2 (ix) 15 1/25 It can be written as = 15 + 1/25 Multiplying and dividing by 4 to get 100 as denominator = 15 + [(1/25) × (4/4)] On further calculation = 15 + 4/100 By addition = 15.04 (x) 111/250 It can be written as = 111 × [(1/250) × (4/4)] On further calculation = 444/1000 By division = 0.444 2. Express the following decimals as fractions in the lowest form: (i) 0.5 (ii) 2.5 (iii) 0.60 (iv) 0.18 (v) 5.25 (vi) 7.125 (vii) 15.004 (viii) 20.375 (ix) 600.75 (x) 59.48 Solution: (i) 0.5 It can be written as = 5/10 By division = 1/2 (ii) 2.5 It can be written as = 25/10 By division = 5/2 (iii) 0.60 It can be written as = 60/100 By division = 3/5 (iv) 0.18 It can be written as = 18/100 By division = 9/50 (v) 5.25 It can be written as = 525/100 By division = 21/4 (vi) 7.125 It can be written as = 7125/1000 By division = 57/8 (vii) 15.004 It can be written as = 15004/1000 By division = 3751/250 (viii) 20.375 It can be written as = 20375/1000 By division = 163/8 (ix) 600.75 It can be written as = 60075/100 By division = 2403/4 (x) 59.48 It can be written as = 5948/100 By division = 1487/25Read More
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