Playing with Numbers

NCERT Exercise 3.1 Solution class 6 math

Question (1) Write all the factors of the following numbers:

(a) Find all the factors of 24

Solution

24 ÷ 1 = 24

Thus, 24 = 24 × 1

24 ÷ 2 = 12

Thus, 24 = 12 × 2

24 ÷ 3 = 8

Thus, 24 = 8 × 3

24 ÷ 4 = 6

Thus, 24 = 6 × 4

Thus, factors of 24 = 1, 2, 3, 4, 6, 8, 12, and 24 Answer

(b) Find all the factors of 15

Solution

15 ÷ 1 = 15

Thus, 15 = 15 × 1

15 ÷ 3 = 5

Thus 15 = 3 × 5

Thus, factors of 15 = 1, 3, 5, and 15 Answer

(c) Find all the factors of 21

Solution

21 ÷ 1 = 21

Thus, 21 = 21 × 1

21 ÷ 3 = 7

Thus, 21 = 7 × 3

Thus, factors of 21 = 1, 3, 7, and 21 Answer

(d) Find all the factors of 27

Solution

27 ÷ 1 = 27

Thus, 27 = 1 × 27

27 ÷ 3 = 9

Thus, 27 = 3 × 9

Thus, factors of 27 = 1, 3, 9, and 27 Answer

(e) Find all the factors of 12

12 ÷ 1 = 12

Thus, 12 = 1 × 12

12 ÷ 2 = 6

Thus, 12 = 2 × 6

12 ÷ 3 = 4

Thus, 12 = 3 × 4

Thus, factors of 12 = 1, 2, 3, 4, 6, and 12 Answer

(f) Find all the factors of 20

Solution

20 ÷ 1 = 20

Thus, 20 = 1 × 20

20 ÷ 2 = 10

Thus, 20 = 2 × 10

20 ÷ 4 = 5

Thus, 20 = 4 × 5

Thus, factors of 20 = 1, 2, 4, 5, 10, and 20 Answer

(g) Find all the factors of18

Solution

18 ÷ 1 = 18

Thus, 18 = 1 × 18

18 ÷ 2 = 9

Thus, 18 = 2 × 9

18 ÷ 3 = 6

Thus, 18 = 3 × 6

Thus, factors of 18 = 1, 2, 3, 6, 9, and 18 Answer

(h) Find all the factors of 23

Solution

23 ÷ 1 = 23

Thus, factors of 23 = 1, and 23 Answer

(i) Find all the factors of 36

Solution

36 ÷ 1 = 36

Thus, 36 = 1 × 36

36 ÷ 2 = 18

Thus, 36 = 2 × 18

36 ÷ 3 = 12

Thus, 36 = 3 × 12

36 ÷ 4 = 9

Thus, 36 = 4 × 9

36 ÷ 6 = 6

Thus, 36 = 6 × 6

Thus, factors of 36 = 1, 2, 3, 4, 6, 9, 12, 18, and 36 Answer

Question (2) Write first five multiples of:

(a) Find five multiples of 5

Solution

First multiple of 5

= 5 × 1 = 5

Second multiple of 5

= 5 × 2 = 10

Third multiple of 5

= 5 × 3 = 15

Fourth multiple of 5

= 5 × 4 = 20

And, the fifth multiple of 5

= 5 × 5 = 25

Thus, 5 multiples of 5 = 5, 10, 15, 20, and 25 Answer

(b) Find five multiples of 8

Solution

First multiple of 8

= 8 × 1 = 8

Second multiple of 8

= 8 × 2 = 16

Third multiple of 8

= 8 × 3 = 24

Fourth multiple of 8

= 8 × 4 = 32

And, the fifth multiple of 8

= 8 × 5 = 40

Thus, 5 multiples of 8 = 8, 16, 24, 32, and 40 Answer

(c) Find five multiples of 9

Solution

First multiple of 9

= 9 × 1 = 9

Second multiple of 9

= 9 × 2 = 18

Third multiple of 9

= 9 × 3 = 27

Fourth multiple of 9

= 9 × 4 = 36

And, the fifth multiple of 9

= 9 × 5 = 45

Thus, 5 multiples of 9 = 9, 18, 27, 36, and 45 Answer

Question (3) Match the items in column I with the items in column 2

Answer

Question (4) Find all the multiples of 9 upto 100.

Solution

(1) 9 × 1 = 9

(2) 9 × 2 = 18

(3) 9 × 3 = 27

(4) 9 × 4 = 36

(5) 9 × 5 = 45

(6) 9 × 6 = 54

(7) 9 × 7 = 63

(8) 9 × 8 = 72

(9) 9 × 9 = 81

(10) 9 × 10 = 90

(11) 9 × 11 = 99

Thus, there are total eleven multiples of 9 upto 100 which are equal to 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99 Answer