**NCERT Solutions for Class 6 Maths Chapter 3**: NCERT Solutions for Class 6 Maths Chapter 3 **Playing With Numbers** Exercise 3.4

- Class 6 Maths Chapter 3 Exercise 3.1
- Class 6 Maths Chapter 3 Exercise 3.2
- Class 6 Maths Chapter 3 Exercise 3.3
- Class 6 Maths Chapter 3 Exercise 3.4
- Class 6 Maths Chapter 3 Exercise 3.5
- Class 6 Maths Chapter 3 Exercise 3.6
- Class 6 Maths Chapter 3 Exercise 3.7

## NCERT Solutions for Class 6 Maths Chapter 3 Whole Numbers Exercise 3.4

1. Find the common factors of:

(A) 20 and 28

(B) 15 and 25

(C) 35 and 50

(D) 56 and 120

**Solution:**

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

Factors of 28=1,2,4,7,14,28

Common factors =1,2,4

(B) Factors of 15=1,3,5,15

Factors of 25=1,5,25

Common factors =1,5

(C) Factors of 35=1,5,7,35

Factors of 50=1,2,5,10,25,50

Common factors =1,5

(D) Factors of 56=1,2,4,7,8,14,28,56

Factors of 120=1,2,3,4,5,6,8,10,12,15,20,24,30,40,60,120

Common factors =1,2,4,8

2. Find the common factors of:

(A) 4, 8 and 12

(B) 5, 15 and 25

**Solution:**

(A) 4,8,12

Factors of 4=1,2,4

Factors of 8=1,2,4,8

Factors of 12=1,2,3,4,6,12

Common factors =1,2,4

(B) 5,15, and 25

Factors of 5=1,5

Factors of 15=1,3,5,15

Factors of 25=1,5,25

Common factors =1,5

3. Find the first three common multiples of:

(A) 6 and 8

(B) 12 and 18

**Solution:**

**(A) 6 and 8**

Multiple of 6=6,12,18,24,30

Multiple of 8=8,16,24,32

3 common multiples =24,48,72

**(B) 12 and 18**

Multiples of 12=12,24,36,78

Multiples of 18=18,36,54,72

3 common multiples = 36,72,108

4. Write all the numbers less than 100 which are common multiples of 3 and 4.

**Solution:**

Multiples of 3=3,6,9,12,15…

Multiples of 4=4,8,12,16,20…

Common multiples =12,24,36,48,60,72,84,96

5. Which of the following numbers are co-prime?

(A) 18 and 35

(B) 15 and 37

(C) 30 and 415

(D) 17 and 68

(E) 216 and 215

(F) 81 and 16

**Solution:**

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

Factors of 35=1,5,7,35

Common factor =1

Therefore, the given two numbers are co-prime

(B) Factors of 15=1,3,5,15

Factors of 37=1,37Common factors =1

Therefore, the given two numbers are co-prime.

(C) Factors of 30=1,2,3,5,6,10,15,30

Factors of 415=1,5,83,415

Common factors =1,5

As these numbers have a common factor other than 1, the given two numbers are not co-prime.

(D) Factors of 17=1,17

Factors of 68=1,2,4,17,34,68

Common factors =1,17

As these numbers have a common factor other than 1, the given two numbers are not co-prime.

(E) Factors of 216=1,2,3,4,6,8,9,12,18,24,27,36,54,72,108,216

Factors of 215=1,5,43,215

Common factors =1

Therefore, the given two numbers are co-prime.

(F) Factors of 81=1,3,9,27,81

Factors of 16=1,2,4,8,16

Common factors =1

Therefore, the given two numbers are co-prime