Page 296 - Start Up Mathematics_6

1. 1 6. HCF × Product of
2. All composite numbers, i.e., 4, 6, 8, 9, ... upto 25 have Numbers HCF LCM LCM numbers
more than two jumpers landing.
3. All prime numbers have only two jumpers landing. (a) 12, 18 6 36 216 216
4. 24 5. (a) 6 (b) 1 (c) 4 (b) 15, 20 5 60 300 300
(c) 98, 124 2 6,076 12,152 12,152
Review Exercises
Multiple Choice Questions HCF × LCM = Product of the two numbers.
1. c 2. a 3. a 4. c 5. b 6. b Values and Life Skills

Solve Mentally 12,240 cm
True or False Exemplar Problems
1. False 2. True 3. False 4. False 1. a 2. c 3. d 4. c 5. True
5. True 6. True 7. False 6. False 7. True 8. 60 L
Fill in the Blanks 9. Brand A : 35 packets Brand B : 28 packets
1. abundant 2. 19 3. 8 4. 4 5. symmetric Brand C : 20 packets
Answer in One Word or a Line Chapter 4
1. 7, 14, 21 2. 1 3. 3
4. No, 8 and 9 are coprime but none of them is prime; Yes Exercise 4.1
5. ab 1. Open figures—(iii), (iv); Closed figures—(i), (ii), (v)
6. LCM > HCF, as multiples are always greater than factors. 2. (a) True (b) True (c) False (d) False (e) False

Let’s Evaluate (f) False (g) False (h) True (i) False
1. (a) 3 + 17 + 23 (b) 13 + 17 + 31 (j) False (k) True
or 7 + 13 + 23 or 11 + 13 + 37 3. (a) 10 (b) 4 (c) 4
(c) 11 + 31 + 41 (d) Lines: AB, AC, AD, AE, BC, BD, BE, CD, CE, DE
or 23 + 29 + 31 (Note: Answers can vary) 4. 1, 3 5. k, l, m and n are also concurrent.
2. (a), (c) 3. 999; 3 × 37 Exercise 4.2
3
4. No, not necessarily, for example, 2 + 5 = 7, which is odd. 1. (a) False (b) True (c) False (d) False (e) True
5.
2. 14 cm
Divisible by
Number 3. T (a) Exterior: P, Q
2 3 4 5 6 8 9 10 11 P R
5,444 Y N Y N N N N N N Q S (b) Interior: R, S
67,859 N N N N N N N N Y (c) On the circle: T, U
5,64,382 Y N N N N N N N N U
9,00,001 N N N N N N N N N 4. (a) Infinite (b) Infinite (c) One
8,01,020 Y N Y Y N N N Y Y 5. (a) O (b) OR
8,43,264 Y Y Y N Y Y Y N N (c) PQ (d) POR

6. 30 7. 1,00,200 (e) semicircle PRQ (f) PR
Thinking Skills

1. No, the number 20 is divisible by 2 and 4, but it is not 6. BD lies in the interior and
divisible by 8. AC lies in its exterior.

2. 1 and 4 3. 129
4.  4 = 2 ∴ factors are 1, 2, 2 , 2 , 2 , ... 2 10
2
3
5
10
4
5. In any three consecutive numbers, you will always have Review Exercises
a multiple of two and three each. Therefore, product of Multiple Choice Questions
any three consecutive numbers is always divisible by 6. 1. c 2. a 3. d 4. a 5. c 6. c
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