Exercise 3.1

Class 6 Mathematics Chapter 3 |
Playing with Numbers Exercise 3.1

Question 1:Write all the factors of the following numbers:
(a) 24 (b) 15 (c) 21 (d) 27 (e) 12 (f) 20 (g) 18 (h) 23 (i) 36

Answer 1:
(a) 24 = 1 x 24 = 2 x 12 = 3 x 8 = 4 x 6 = 6 x 4
Factors of 24 = 1, 2, 3, 4, 6, 12, 24

(b) 15 = 1 x 15 = 3 x 5 = 5 x 3
Factors of 15 = 1, 3, 5, 15

(c) 21 = 1 x 21 = 3 x 7 = 7 x 3
Factors of 21 = 1, 3, 7, 21

(d) 27 = 1 x 27 = 3 x 9 = 9 x 3
Factors of 27 = 1, 3, 9, 27

(e) 12 = 1 x 12 = 2 x 6 = 3 x 4 = 4 x 3
Factors of 12 = 1, 2, 3, 4, 6, 12

(f) 20 = 1 x 20 = 2 x 10 = 4 x 5 = 5 x 4
Factors of 20 = 1, 2, 4, 5, 10, 20

(g) 18 = 1 x 18 = 2 x 9 = 3 x 6
Factors of 18 = 1, 2, 3, 6, 9, 18

(h) 23 = 1 x 23
Factors of 23 = 1, 23

(i) 36 = 1 x 36 = 2 x 18 = 3 x 12 = 4 x 9 = 6 x 6
Factors of 36 = 1, 2, 3, 4, 6, 9, 12, 18, 36

Question 2: Write first five multiples of:

(a) 5  (b) 8  (c) 9

Answer 2: (a) 5 x 1 = 5

5 x 2 = 10

5 x 3 = 15,

5 x 4 = 20

5 x 5 = 25

First five multiples of 5 are 5, 10, 15, 20, 25

(b) 8 x 1 = 8

8 x 2 = 16

8 x 3 = 24

8 x 4 = 32

8 x 5 = 40

First five multiples of 8 are 8, 16, 24, 32, 40.

(c) 9 x 1 = 9

9 x 2 = 18

9 x 3 = 27

9 x 4 = 36

9 x 5 = 45

First five multiples of 9 are 9, 18, 27, 36, 45.

Question 3: Match the items in column 1 with the items in column 2

Column 1       Column 2

(i) 35          (a) Multiple of 8

(ii) 15         (b) Multiple of 7

(iii) 16        (c) Multiple of 70

(iv) 20        (d) Factor of 30

(v) 20          (e) Factor of 50

Answer 3: (i)  : (b)

(ii) : (d),

(iii) : (a)

(iv) : (f),

(v) : (e)

Question 4: Find all the multiples of 9 up to 100.

Answer 4: Multiples of 9 up to 100 are: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99