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
2. Find the common factors of:
(a) 4.8 and 12 (b) 5,15 and 25
3. Find first three common multiples of :
(a) 6 and 8 (b) 12 and 18
4. Write all the numbers less than 100 which are common multiples of 3 and 4
5. Which of the following numbers are co-prime?
(a) 18 and 35 (b) 15 and 37 (C) 30 and 415
81 and 16
Answers
Answer:
Solution:
We will be using the concept of factors to solve this.
(a) Given numbers are: 20 and 28
Factors of 20 are 1, 2, 4, 5, 10, 20
Factors of 28 are 1, 2, 4, 7, 28
Therefore, the common factors of 20, and 28 are 1, 2, and 4.
(b) Given numbers are:15 and 25
Factors of 15 are 1, 3, 5, 15
Factors of 25 are 1, 5, 25
Therefore, the common factors of 15 and 25 are 1 and 5.
(c) Given numbers are:35 and 50
Factors of 35 are:1, 5, 7, 35
Factors of 50 are: 1, 2, 5, 10, 50
Therefore, the common factors of 35 and 50 are 1 and 5.
(d) Given numbers are: 56 and 120
Factors of 56 are 1, 2, 4, 7, 8, 14, 28, 56
Factors of 120 are 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 30, 40, 60, 120
Therefore, the common factors of 56 and 120 are 1,2, 4, and 8.
You can also check your answer on Online Common Factor Calculator.
NCERT Solutions for Class 6 Maths Chapter 3 Exercise 3.4 Question 1
Find the common factors of: (a) 20 and 28 (b) 15 and 25 (c) 35 and 50 (d) 56 and 120
Summary:
(a) The common factors of 20 and 28 are 1, 2, and 4. (b) The common factors of 15 and 25 are 1 and 5. (c) The common factors of 35 and 50 are 1 and 5. (d) The common factors of 56 and 120 are 1,2,4 and 8.