The least common multiple of 9 and 4 How do you calculate that?

The least common multiple of 9 and 4 How do you calculate that?

thirty-six
The factor of 4 is only 1, 2 and 4
The factor of 9 is only 1, 3 and 9
So they have no common factor other than 1, so the least common multiple is 4x9 = 36