HCF (Highest Common Factor)

Highest Common Factor of Say 24 and 56. Since both the numbers are less then 100 we can solve it using 2,3,5, and 7 prime factors.

So first you do prime factorization of 24

2 | 24

2 | 12

2 | 6

3 |  3

  |  1 

So Prime Factors of 24 is  2 x 2 x 2 x 3

Similarly the prime factorization of 56 is:

2 | 56

2 | 28

2 | 14

7 | 7

   | 1

So you have prime factors 2 x 2 x 2 x 7 = 56

Now lets see the common factors between the two

24 = 2 x 2 x 2 x 3

56 = 2 x 2 x 2 x 7

Here  2 repeated 3 times is common in both, hence the highest common factor is 2 x 2 x 2 = 8