Question

Find the HCF of 30 and 45.

Answer 1

HCF of 30 and 45 is 15.

Explanation:

Factors of 30 : 1, 2, 3, 5, 6, 10, 15, 30.

Factors of 45 : 1, 3, 5, 9, 15, 45.

Common Factors : 1, 3, 5, 15

Highest Common Factor : 15

Answer 2

15

Explanation:

Since 30 and 45 are relatively small numbers, it's not a big deal to list every single one of their common factors.

Factors of 30: 1, 2, 3, 5, 6, 10, 15, 30

Factors of 45: 1, 3, 5, 9, 15, 45

Now that we have a list, it's easy to see which number is the highest common factor, which is, of course, 15.