Edexcel Maths Answer Key
Edexcel IGCSE Maths 1
Answers to activities and exercises
Unit 1
1NUMBER 11 EXERCISE 1
1 6
2 3 1 3
2 7
2 3 3 , 75% 4
11 0.15, 15% 16 3 21
1 4 11 6
12 0.075, 7.5% 17 3 22
2 5 41 7
14 19
EXERCISE 1*
1 6 11 16
2 7 3 8 2 3 3 40
2 7 12
2 3 3 40 4 5
3 8 13
3 18 1 15 4 9
4 9 14
7 11 5 6 3 8
5 10 15
1 2 5 6 7 40
17 680 22 3.1 27 41.86
18 910 23 24 28 49.88
19 0.765 24 18
20 0.095 25 26.25
21 39 26 42.84
EXERCISE 2
1 6 11 16 5 –20 –6 3 2 7 12 17 –8 –3 –6 10 3 8 13 18 13 –10 –2 4 4 –17 9 –12 14 –5 5 13 10 28 15 3
EXERCISE 2*
1 –2 6 10 11 12 16 74 2 6 7 18 12 18 17 144 3 23 8 10 13 36 18 196 4 5 9 12 14 13 5 18 10 2
2 3
15 49
EXERCISE 3
1 1.8 6 12.6 litres 11 15% 2 0.272 km 7 £31.80 12 6% 3 5.52 m 8 £64.80 13 10% 4 1.38 cm 9 £45.50 14 15% 5 0.684 10 £71.20 15 5%
IGCSE Maths Answers – Unit 1
1
1 3 1 8 , 20% 5 7 , 35% 13 20 5 18 2 7
3
4 9
2 3 1 , 0.25 4 3 , 37.5% 8 7 3
1 2 1 10 , 0.125 8 2 15 2 3 18 20 5
5
16 5.94 m 18 $9120
17 Percentage increase in value = 19 688 20
468 7800
100 = 6%
60 80 = 2.70% increase. = 3.95% increase. 80 2000
EXERCISE 3*
1 0.75 6 106.25 11 15% IGCSE Maths Answers – Unit 1 2 21 kg 7 68.005 km 12 $836 3 $171 8 86.1 kg 4 11.7 km 9 $80.04 5 52.5 10 $89.18
4.25 34
13 Profit = 4.25; percentage profit =
100 = 12.5%
14 39% 15 0.0402% 16 33.3% 17 250% 18 11.1%; 12.5% 19 There are 500 million telephones in the world, 60 000 in Ethiopia. Population of Ethiopia is 30 million. 20 1976 1986 1996 Largest tin (p/g) Smallest tin (p/g) 0.0359 0.0493 0.0607 0.1 0.0738 0.16 % increase in cost ’86–’96 21.6 60
% increase in cost ’76–’86 Largest tin Smallest tin 69.1 102.8
Inflation was much higher between 1976 and 1986. If the larger tin were bought in 1976 you would get 37.3% more for your money. In 1986 you would get 64.7% more for your money and in 1996 you would get 117% more.
ACTIVITY 1
Neurons: 1011 Connections: 1015
Answers to activities and exercises
Unit 1
1NUMBER 11 EXERCISE 1
1 6
2 3 1 3
2 7
2 3 3 , 75% 4
11 0.15, 15% 16 3 21
1 4 11 6
12 0.075, 7.5% 17 3 22
2 5 41 7
14 19
EXERCISE 1*
1 6 11 16
2 7 3 8 2 3 3 40
2 7 12
2 3 3 40 4 5
3 8 13
3 18 1 15 4 9
4 9 14
7 11 5 6 3 8
5 10 15
1 2 5 6 7 40
17 680 22 3.1 27 41.86
18 910 23 24 28 49.88
19 0.765 24 18
20 0.095 25 26.25
21 39 26 42.84
EXERCISE 2
1 6 11 16 5 –20 –6 3 2 7 12 17 –8 –3 –6 10 3 8 13 18 13 –10 –2 4 4 –17 9 –12 14 –5 5 13 10 28 15 3
EXERCISE 2*
1 –2 6 10 11 12 16 74 2 6 7 18 12 18 17 144 3 23 8 10 13 36 18 196 4 5 9 12 14 13 5 18 10 2
2 3
15 49
EXERCISE 3
1 1.8 6 12.6 litres 11 15% 2 0.272 km 7 £31.80 12 6% 3 5.52 m 8 £64.80 13 10% 4 1.38 cm 9 £45.50 14 15% 5 0.684 10 £71.20 15 5%
IGCSE Maths Answers – Unit 1
1
1 3 1 8 , 20% 5 7 , 35% 13 20 5 18 2 7
3
4 9
2 3 1 , 0.25 4 3 , 37.5% 8 7 3
1 2 1 10 , 0.125 8 2 15 2 3 18 20 5
5
16 5.94 m 18 $9120
17 Percentage increase in value = 19 688 20
468 7800
100 = 6%
60 80 = 2.70% increase. = 3.95% increase. 80 2000
EXERCISE 3*
1 0.75 6 106.25 11 15% IGCSE Maths Answers – Unit 1 2 21 kg 7 68.005 km 12 $836 3 $171 8 86.1 kg 4 11.7 km 9 $80.04 5 52.5 10 $89.18
4.25 34
13 Profit = 4.25; percentage profit =
100 = 12.5%
14 39% 15 0.0402% 16 33.3% 17 250% 18 11.1%; 12.5% 19 There are 500 million telephones in the world, 60 000 in Ethiopia. Population of Ethiopia is 30 million. 20 1976 1986 1996 Largest tin (p/g) Smallest tin (p/g) 0.0359 0.0493 0.0607 0.1 0.0738 0.16 % increase in cost ’86–’96 21.6 60
% increase in cost ’76–’86 Largest tin Smallest tin 69.1 102.8
Inflation was much higher between 1976 and 1986. If the larger tin were bought in 1976 you would get 37.3% more for your money. In 1986 you would get 64.7% more for your money and in 1996 you would get 117% more.
ACTIVITY 1
Neurons: 1011 Connections: 1015