| 18 | = | 1 x 2 x 3 x 3 |
| 15 | = | 1 x 3 x 5 |
HCF = 1 x 3 x 3 = 9
Find prime factors of number 18
18 = 1 x 2 x 3 x 3
Find prime factors of number 15
15 = 1 x 3 x 5
Find common factors and multiply them to get HCF.
| 18 | = | 1 x 2 x 3 x 3 |
| 15 | = | 1 x 3 x 5 |
HCF = 1 x 3 x 3 = 9