How do you find the LCM of 18 and 60?

Answer 1

To find the Least Common Multiple, find the factors common to both numbers, and multiply them once, then multiply that by all other factors.

So for 18 and 60:

• Factors of 18: 1, 2, 3, 3
• Factors of 60: 1, 2, 2, 3, 5

So the factors common to both: 1, 2, & 3

The other factors: another 3 (from 18), another 2 (from 60) and 5 (from 60).

So we have the (1 x 2 x 3) x (3 x 2 x 5) = 180

Answer 2

You can list the multiples.

18, 36, 54, 72, 90, 108, 126, 144, 162, 180, 198

60, 120, 180, 240

The LCM is 180.