Page 215 - ICSE Math 4
P. 215
2. (a) 2, 4 and 6 (b) 4 and 14 (c) 6 and 3 Exercise 7.4
(d) 5 (e) 4 and 2 1. (a), (b), (e) and (f) 2. (b), (c), (e) and (f)
3. Yes 4. Yes 3. (a), (b) and (e) 4. (a), (b), (e) and (f)
5. (a) 1, 2 and 4 (b) 1 and 3 5. (a), (b) and (d) 6. (a), (b) and (e)
(c) 1 and 2 (d) 1, 2, 4, 5 and 20
Exercise 7.5
Exercise 7.2 1. (a) 2 (b) 9 (c) 3 (d) 14 (e) 9 (f) 2
1. (a) mul ple (b) greater than 2. 12
3. (a) 6, 12, 18, 24, 30; 6 (b) 15, 30, 45, 60, 75; 15
(c) 9, 18, 27, 36, 45, 54, 63, 72 and 81
(d) infi nite (c) 120, 240, 360, 480, 600; 120
(d) 60, 120, 180, 240, 300; 60
2. (a) 7, 14, 21, 28, 35 (b) 11, 22, 33, 44, 55
(c) 14, 28, 42, 56, 70 (d) 8, 16, 24, 32, 40 (e) 48, 96, 144, 192, 240; 48
(f) 150, 300, 450, 600, 750; 150
(e) 6, 12, 18, 24, 30
3. (a) 48; 84 (b) 72; 126 (c) 16; 28 4. (a) 9 (b) 48 (c) 24 (d) 10 (e) 12 (f) 180
(d) 64; 112 (e) 20; 35 Review Exercise
4. (a) 24, 650 and 418 (b) 65 and 950 1. (a) even (b) 1 (c) 47 (d) 2
(c) 72 and 615 (d) 81 and 18 (e) smallest (f) 5, 10 and 15 (g) composite
5. (a) 21 and 42 (b) 16 and 64 (c) 18 and 36 2. (a) (iii) (b) (ii) (c) (iv) (d) (ii) (e) (ii)
(Answers may vary) 3. (a) 2, 3; 2, 5
(b) (i) 2, 6, 7, 21 and 42 (ii) 2, 3, 4, 6 and 12
Exercise 7.3
(iii) 1, 2, 4, 7 and 14 (iv) 2, 5, 10, 25 and 50
1. (a) 2; 3 (b) 4 (c) even (d) 0; 1
(Answers may vary)
(e) 2; 5 (f) two (g) 25 (h) 2; 3
(c) (i) 13, 39, 65, 91, 117 (ii) 9, 27, 45, 63, 81
(i) Prime factoriza on
(iii) 17, 51, 85, 119, 153 (iv) 21, 63, 105, 147, 189
2. (a) 21 , 27 , 30, 39 , 42, 45
(d) (i) 52 = 2 × 2 × 13 (ii) 124 = 2 × 2 × 31
(b) 24, 28, 32, 36, 40, 44
(iii) 17 = 1 × 17 (iv) 147 = 3 × 7 × 7
(c) 25 , 30, 35 , 40, 45 , 50
(e) Yes, 248 is a mul ple of 4.
(d) 24, 30, 36, 42, 48, 54
(f) Yes, 12 is a factor of 2,460.
3. 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47
(g) Students to do on their own.
4. 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 4. (a) 8 (b) 11 (c) 2 (d) 24
51, 52, 54, 55, 56, 57, 58, 60, 62, 63, 64, 65, 66, 68, 69
5. (a) 72 (b) 119 (c) 60 (d) 60
5. Prime numbers: 67, 113, 137, 71
Progress Worksheet
Composite numbers: 123, 125
6. (a) 24 (b) 52 1. (a) the number itself (b) 1 (c) even
(d) 43 (e) 1
6 4 2 26 2. (a) True (b) True (c) False (d) False
3. (a), (b) and (d) 4. 9
2 3 2 2 2 13 5. (a) 56 = 2 × 2 × 2 × 7 (b) 72 = 2 × 2 × 2 × 3 × 3
(c) 16 (d) 12 (c) 68 = 2 × 2 × 17 (d) 81 = 3 × 3 × 3 × 3
(e) 26 = 2 × 13
4 4 6. (a) 28, 56, 84, 112, 140; 28 (b) 18, 36, 54, 72, 90; 18
4 3
(c) 14, 28, 42, 56, 70; 14 (d) 15, 30, 45, 60, 75; 15
2 2 2 2
2 2 7. (a) 36 (b) 16
(e) 45 (f) 36 2 18 2 8
3 15 4 9 2 9 2 4
3 3 2 2
3 5 2 2 3 3
36 = 2 × 2 × 3 × 3 16 = 2 × 2 × 2 × 2
(Answers may vary)
Chapter 8: Frac ons
7. (a) 63 = 3 × 3 × 7 (b) 108 = 2 × 2 × 3 × 3 × 3
(c) 314 = 2 × 157 (d) 96 = 2 × 2 × 2 × 2 × 2 × 3 Exercise 8.1
(e) 280 = 2 × 2 × 2 × 5 × 7 (f) 121 = 11 × 11 1. (a) F (b) W (c) W (d) F (e) W (f) F
8. (a) 9, 11, 13, 15, 17 (b) 10, 12, 14, 16, 18 2. (a) Numerator: 3 (b) Numerator: 4
(c) 11, 13, 17, 19, 23 (d) 10, 12, 14, 15, 16 Denominator: 5 Denominator: 7
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