Question

Find the HCF of 32 20 and 72

Answer 1

Factorize :

20 = 22 • 5

32 = 25

72 = 23 • 32

Build a prime factors table

Number of times each prime factor

appears in the factorization of :

Prime

Factor Number

20 Number

32 Number

72 G.C.F

(min)

2 2 5 3 2

3 0 0 2 0

5 1 0 0 0

GCF = 22

Greatest Common Factor is :

4

Answer 2

Required Answer:

H.C.F. of the following numbers is 4.

(See attachment)

What is HCF? How to Find HCF?

HCF stands for Greatest Common Factor. HCF gives us the greatest factor present between group of numbers. Those numbers can be 2 to infinite.

If we need to find HCF, follow these steps:

1. Find the prime factorisation of all the numbers.
2. Start from the smallest number which is divisible.
3. Then after doing prime factorisation of all numbers, write their factorised value separately. (as written in attachement)
4. Now find the common numbers appearing in all the numbers (like 2×2 are common in all 3 numbers).
5. Now take out the common numbers and multiply them. The answer we got is the HCF.

The example we took was from the question only. You can take more examples.

_______________