Question

What is the greatest common factor of 30, 45, and 90?

Answer 1

15

The factors of 30 are: 1, 2, 3, 5, 6, 10, 15, 30

The factors of 45 are: 1, 3, 5, 9, 15, 45

The factors of 90 are: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90

Then the greatest common factor is 15.