Page 314 - ICSE Math 8

Chapter 4 3. 9 4. 6 3 4

Exercise 4.1 8 4 × 7 5
3 1 7 0
1. (a) –1,728 (b) –12,167 (c) –42,875 (d) –74,088 7 5 3 4 4 3 8 ×
2. (a), (b) and (c) 3. (a) –19 (b) –46 (c) –28 4 7 5 5 0
(d) –121 (e) –95 4. (a) 250.047 (b) –0.009261 6 2
2,197 21 − 29,791 1
(c) or 34 (d) (e) 0.000512 5.
64 64 216 41
(f) –345.948408 5. Yes; 12
43
Exercise 4.2 13 47 17 31 53
1. (a) 6 (b) 4 (c) 18 (d) 2 (e) 9 2. (a) 5 (b) 2
(c) 2 (d) 45 (e) 5 3. (a) 9 (b) 16 (c) 18 31
(d) 25 (e) 30 (f) 34 (g) 42 4. 130 m 29
5. (a) 68 (b) 95 (c) 86 (d) 59 (e) –70
Mental Maths
Exercise 4.3 1. (a) (i) (b) (ii) (c) (i) (d) (iii) (e) (iv)
1. (a) –7 (b) 0.9 (c) –19 (d) –72 (e) 1.3 2. (a) True (b) True (c) False (d) False (e) False
3. (a) 22 (b) –45 (c) 28 (d) 48 (e) 120p (f) 11.1 Practice Time
2
3 9 − 15
(g) 1 (h) or 0.75 4. (a) (b) 1. x = 4 2. y = 2 3. X = 5
4 13 17
29 21 − 28 4. A = 8, B = 6, C = 4, D = 4, E = 5, F = 6, G = 3 and H = 6
(c) (d) (e) 5. 7 6. 2 7. 3.3 m 5. (a) 9(a – c)
27 − 10 19
13 6. A 3-digit number 100a + 10b + c is divisible by 6 if c
8. cm or 1.44 cm 9. 1,728 10. 3,025 is 0, 2, 4, 6 or 8 and a + b + c is divisible by 3.
9
Mental Maths 7. No, because 9 + 5 = 14, which is not divisible by 3.
1. (a) (iii) (b) (ii) (c) (iii) (d) (iii) 8. 675 and 720
2. (a) True (b) False (c) True (d) True (e) False Think Smart
(f) True (g) False 1.
3. (a) 2 (b) 64 (c) 7 (d) 3 6 7 10 11 12

Practice Time 5 8 9 14 13
1. (a) 6,859 (b) 17,576 (c) 1,17,649 (d) 18,60,867
− 3 4 3 20 15 16
2. 2 3. 5 4. (a) –136 (b) 144 (c) 154 (d)
5 1 2 19 18 17
5. 135 cm

Chapter 5 2. 2 6 1 5
× 4 3 9
Exercise 5.1 2 3 5 3 5
1. (a) 11 (b) 13 2. (a) 4 (b) 9 7 8 4 5 X
3. 14, 11 and 42 respectively 1 0 4 5 0 X X
1 1 4 7 9 8 5
Exercise 5.2
1. 6, 10, 14 Chapter 6
2. (a) 6, 15 (b) 4, 8 (c) 12, 20
3. (a) 234, 324, 342, 432 (b) 234, 243, 324, 342, 423, 432 Exercise 6.1
2. (a) ∈ (b) ∈ (c) ∉ (d) ∈ (e) ∉
4. (a) 35, 200, 750, 625, 130 (b) 200, 750, 130 3. (a) A = {0, 1, 2, 3, 4, 5, 6, 7} (b) B = {3, 5, 7}
5. 0, 3, 6, or 9 6. 2
(c) C = {18, 27, 36, 45, 54, 63, 72, 81, 90}
Exercise 5.3 (d) D = {2, 3, 5} (e) E = {M, A, T, H, E, I, C, S}
1. (a) X = 5, Y = 8 (b) B = 6 4. (a) P = { x: x is a month of a year starting with the
(c) P = 4, Q = 7 (d) R = 2, S = 5 letter J}

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