Page 295 - Start Up Mathematics_6

Exercise 3.2
5. 1. 53, 59, 61, 67, 71, 73, 79, 83, 89, 97
0 1 2 3 4 5 6 7 8 9
2. 42, 44, 46, 48, 50, 52, 54, 56, 58
2 + 7 = 9 3. 1, 3, 5, 7, 9, 11, 13, 15, 17, 19
4. 3, 5 ; 5, 7 ; 11, 13 ; 17, 19 ; 29, 31 ; 41, 43 ; 59, 61 ; 71, 73
5. Prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29
6. 0 3 6 9 12 15 18 Composite numbers: 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20,
3 × 6 = 18 21, 22, 24, 25, 26, 27, 28
7. 25,600 8. 1,73,800 9. 4 6. (a) 2 + 13 or 3 + 5 + 7 (b) 11 + 2 (c) 7 + 13 + 17
10. 10,032 11. (a) 5,050 (b) 2,550 (c) 840 7. (a) 41 + 43 (b) 59 + 61 (c) 17 + 19
Thinking Skills 8. (a) 5 + 37 (b) 3 + 29 (c) 3 + 47
1. Yes, 0; multiplication, 1 9. (a) False (b) False (c) True (d) False
2. No, Absolute value of the difference is equal. (e) False (f) False (g) False (h) True
3. Yes 4. sum Exercise 3.3
5. No, since 3, 1 ∈ W – {4} and 3 + 1 = 4 ∉ W – {4} 1. b, c 2. a, b 3. a, b 4. b, c 5. a, c
∴ closure property of addition is not satisfied. 6. c 7. a, c 8. b, c 9. a, c
6. Yes, since for every a, b, ∈ W – {7} and a × b ≠ 7 10. (a) 2 (b) 1 11. (a) 2 (b) 6 12. (a) 3 (b) 3
∴ closure property of multiplication is satisfied. Exercise 3.4
7. 5 fishermen went to the sea. The expression represents 1. (a) 1, 5 (b) 1, 2, 4 (c) 1, 7 (d) 1, 3
total number of fish caught if 4 fishermen netted 8 fish (e) 1, 2, 4 (f) 1, 3, 5, 15
each and one of them caught only 6 fish. (Note: Answers 2. (a) 24, 48, 72 (b) 18, 36, 54 (c) 50, 100, 150
can vary)
3. 30, 60 4. 1, 3, 5 5. a, b 6. 40
Values and Life Skills Exercise 3.5
1. 1,344 km 2. ` 143
1. (a) 2 × 2 × 2 × 3 × 11 × 11 (b) 2 × 2 × 3 × 5 × 5 × 5
Exemplar Problems (c) 3 × 3 × 3 × 3 × 7 × 7 (d) 7 × 11 × 11 × 11
1. b 2. c 3. c 4. d 5. b (e) 3 × 3 × 17 × 19 (f) 3 × 7 × 13 × 17
6. c 7. (i) (d) (ii) (f) (iii) (b) (iv) (e) (v) (c) 2. 999; 3 × 3 × 3 × 37
8. 891378 3. 10,000; 2 × 2 × 2 × 2 × 5 × 5 × 5 × 5
Quiz 4. 2 × 5 × 11 × 11 × 17
(a) 8 (b) 9 (c) 3 (d) 4, 6 or 8 (e) 3 (f) 6 Puzzle

Chapter 3 LCM of 24 and 28 = 168, ∴ Number of revolutions made by
Exercise 3.1 gear 1 = 168 = 7
24
1. (a) 1, 2, 4, 5, 10, 20 (b) 1, 2, 3, 4. 6, 9, 12, 18, 36 Exercise 3.6
(c) 1, 3, 17, 51 (d) 1, 2, 4, 8, 16, 32, 64
(e) 1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 36, 48, 72, 144 1. (a) 12 (b) 72 (c) 168 (d) 6 (e) 8 (f) 12
(f) 1, 3, 9, 27, 81, 243, 729 2. (a) 342 (b) 60 (c) 1,872 (d) 5,250
2. (a) 7, 14, 21, 28, 35 (b) 13, 26, 39, 52, 65 (e) 1,260 (f) 31,460 3. 138 4. 3 kg
(c) 17, 34, 51, 68, 85 (d) 15, 30, 45, 60, 75 5. 25 cm 6. 10,080 7. 990
3. 11, 22, 33, 44, 55, 66, 77, 88, 99 4. 1, 2, 4, 5, 10, 20 Reason It Out!
1,677 is divisible by 43, hence it is a composite number.

Worksheet
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
2 3 2 5 2 7 2 3 2 11 2 13 2 3 2 17 2 19 2 3 2 23 2 5
4 3 4 9 5 3 7 5 4 3 4 7 11 3 25
6 8 10 4 14 15 8 6 5 21 22 4
6 16 9 10 6
12 18 20 8

12
24

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