Playing With Numbers Class 6 Ex. 3.1
Ncert Class 6 Math Free Solution.
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
Solution 1:-
(a) Factors of 24 are:
24 = 1 x 24;
24 = 2 x 12;
24 = 3 x 8;
24 = 4 x 6
So, all the factors of 24 are :- 1, 2, 3, 4, 6, 8, 12 and 24.
(b) Factors of 15 are:
15 = 1 x 15;
15 = 3 x 5
So, all the factors of 15 are :- 1, 3, 5 and 15.
(c) Factors of 21 are:
21 = 1 x 21;
21 = 3 x 7
So, all the factors of 21 are :- 1, 3, 7 and 21.
(d) Factors of 27 are:
27 = 1 x 27;
27 = 3 x 9.
So, all the factors of 27 are :- 1, 3, 9 and 27.
(e) Factors of 12 are:
12 = 1 x 12;
12 = 2 x 6;
12 = 3 x 4
So, all the factors of 12 are :- 1, 2, 3, 4, 6 and 12.
(f) Factors of 20 are:
20 = 1 x 20;
20 = 2 x 10;
20 = 4 x 5
So, all the factors of 20 are :- 1, 2, 4, 5, 10 and 20.
(g) Factors of 18 are:
18 = 1 x 18;
18 = 2 x 9;
18 = 3 x 6;
So, all the factors of 18 are :- 1, 2, 3, 6, 9 and 18.
(h) Factors of 23 are:
23 = 1 x 23;
So, all the factors of prime number 23 are :- 1 and 23.
(i) Factors of 36 are:
36 = 1 x 36;
36 = 2 x 18;
36 = 3 x 12;
36 = 4 x 9;
36 = 6 x 6;
So, all the factors of 36 are :- 1, 2, 3, 4, 6, 9, 12, 18 and 36.
Question 2 :- Write first five multiples of :-
(a) 5 (b) 8 (c) 9
Solution:
(a) First five multiples of 5 are:
5 x 1 = 5;
5 x 2 = 10;
5 x 3 = 15;
5 x 4 = 20;
5 x 5 = 25;
So, the required multiples of 5 are :- 5, 10, 15, 20 and 25.
(b) First five multiples of 8 are:
8 x 1 = 8;
8 x 2 = 16;
8 x 3 = 24;
8×4 = 32;
8 x 5 = 40;
So, the required multiples of 8 are :- 8, 16, 24, 32 and 40.
(c) First five multiples of 9 are:
9 x 1 = 9;
9 x 2 = 18;
9 x 3 = 27;
9 x 4 = 36;
9 x 5 = 45;
So, the required multiples of 9 are :- 9,18, 27, 36 and 45.
Question 3 :- Match the items in column I with the items in column II.
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) 25 (e) Factor of 50
(f) Factor of 20
Solution 3:-
(i) → (b) {because, 7 x 5 = 35}
(ii) → (d) {because, 15 x 2 = 30}
(iii) → (a) {because, 8 x 2 = 16}
(iv) → (f) {because, 20 x 1 = 20}
(v) → (e) {because, 25 x 2 = 50}
Question 4 :- Find all the multiples of 9 upto 100.
Solution 4:-
9 x 1 = 9;
9 x 2 = 18;
9 x 3 = 27;
9 x 4 = 36;
9 x 5 = 45;
9 x 6 = 54;
9 x 7 = 63;
9 x 8 = 72;
9 x 9 = 81;
9 x 10 = 90;
9 x 11 = 99;
So, all the multiples of 9 upto 100 are :-
9, 18, 27, 36, 45, 54, 63, 72, 81, 90 and 99.
Playing With Numbers Class 6 Exercise. 3.1 for Free