Page 307 - ICSE Math 7

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5. (a) 5. 2,950 km; 2.950 × 10 km
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4 4 4 6. (a) 8.68 × 10 kg (b) 1.439 × 10 m
(b)
–1 –1 2 –1 1 0 1 Exercise 5.4
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3 3 1. ` 1,024 (=2 ) 2. 1,024 people (=4 ) 3. 6,561 likes (=3 )
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6. (a) –7 (b) –2 (c) –5 (d) –24 (e) –5 (f) 10 4. 6,561 people (=3 ) 5. 6,500
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–2 968 –45 1 Mental Maths
7. (a) (b) – (c) (d)
5 49 56 8 1. (a) (iii) (b) (i) (c) (iv) (d) (iii) (e) (iii)
2 –3 77 1
9. 10. 11. 12. 15 g 2. (a) False (b) False (c) True (d) False (e) True
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Think Smart 3. (a) 2; 5 (b) 3 (c) negative (d) a = b (e) 3
15 5 23 (f) n = 0 (g) a (h) 1; 9
1. 2. 3. 4. 210 runs
21 11 30
Practice Time
Chapter 5 1. (a) 15 (b) 1 (c) a (d) 3 (e) 5 (f) x 1 9
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Exercise 5.1 2. 1 13 (b) 30 (c) 2 (d) 8 (e) 2 (f) 1
1. (a) 32 (b) 243 (c) 2,401 (d) 14,641 27 8 1 3 1 1 27 1
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3 2 2
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2. (a) 7 (b) 2 × 3 (c) x y z 3. 7 16 4. (a) + = 1 (b) + = n
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3. (a) 2 × 5 (b) 2 × 3 × 5 (c) (–7) (d) 2 × 5 6 (c) b 3 + a c = 0
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4. (a) 3 > 4 (b) (–2) < 1 (c) 3 > 5 (d) 2 > 6 2 a 2
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5. 1 = 1, 2 = 16, 3 = 81, 4 = 256, 5 = 625 7. (a) –3 7 (b) –2 18 (c) 5z 10
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6. 6 7. (a) –500 (b) 3,888 (c) 30,375 5 7 x y
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8. (a) 2 × 3 (b) 2 × 5 (c) 2 × 5 × 11 (d) 2 11 8. –1 9. (a) 257 (b) 52 (c) 31 (d) –18 = –3 3
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3 5 (–3) 7 (–5) 6 11 6 9
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9. (a) (b) (c) (d) 10. (a) 10 (b) 1 (c) (d) 24b c
5 5 5 7 9 6 22 6 250
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10. (a) 3 3 = 3 3 (b) (c) –5 4 = –5 4 (d) (–1) 3 Think Smart
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10 3 2 × 5 3 3 6 6 4 2 × 3 4 (5) 3 1. 1,92,000 km 2. 4.06 × 10 miles
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Exercise 5.2 3. Copper (8.96) > Chlorine (2.95 × 10 ) > Oxygen (1.429
–3
1
8
16
–1
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1. 2 2. 2 3. –2 4. (a) (–3) (b) 6 (c) 3 (d) (–5) 0 × 10 ) > Nitrogen (1.2506 × 10 ) > Helium (1.764 ×
–3
–3
m n
–4
–5
mn
5. (a) False,  a b ≠ (ab) (b) False,  8 < 9 10 ) > Hydrogen (8.388 × 10 )
0
n n
n
(c) True,  a b = (ab) (d) True,  a = 1 where a ≠ 0 Chapter 6
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3 4
6. (a) (b) 25 (c) a b (d) 640
270 Exercise 6.1
6 12 5 18 –1 63 –3 25 1. (a) Yes (b) No (c) Yes (d) Yes (e) No (f) Yes
7. (a) (b) (c) (d)
7 9 3 5 2. (a) True (b) False (c) False (d) True (e) True
0
8. (a) –3 1 (b) (–3) (c) –2 6 (f) False
31 5 3. (a) {21, 23, 25} (b) X = {E, X, T, N, S, I, O}
1 1,029 –1 27 (c) X = {12, 14, 15, 16, 18} (d) Y = {8, 9, 10, ...}
9. (a) (b) (c) (d)
9 625 16 8,000 (e) A = {0, 1, 4, 9, 16, 25} (f) {1, 2, 3, 4, 6, 12}
0
10. 10 11. (a) 3 (b) 1 (c) 66 (d) 4 4. (a) X = {x | x = 10n, n ∈ N}
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12. (a) 1 (b) 64 (c) –4 (d) 15 13. 14. 81 (b) A = {x | x is a month starting with letter J}
81 729 15 2 9 256 (c) Y = {x | x is an odd number greater than 20}
Exercise 5.3  1 
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1. (a) 3 × 10 + 5 × 10 + 6 × 10 + 7 × 10 + 8 × 10 + 0 × 10 0 (d) B = xx| = n n , ∈ N n, ≤  5 
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(b) 4 × 10 + 6 × 10 + 0 × 10 + 0 × 10 + 3 × 10 + Exercise 6.2
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4 × 10 + 9 × 10 0 1. (a) Null set (b) Finite set (c) Infinite set
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(c) 3 × 10 + 5 × 10 + 7 × 10 + 9 × 10 + 1 × 10 + (d) Infinite set (e) Null set (f) Finite set
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2 × 10 + 4 × 10 0 2. (a) 3 (b) 2 (c) 9 (d) 4 (e) 4
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2. (a) 2.2 × 10 (b) 4.89213476 × 10 (c) 6.532 × 10 –8 3. (a) True (b) True (c) False (d) True (e) False
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3. 31,622,400 seconds; 3.16224 × 10 seconds (f) True (g) False (h) True
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4. 9,460,800,000,000,000 m; 9.4608 × 10 m 4. (a) f (b) f, {a} (c) f, {a}, {b}, {a, b}
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