Solutions by everydaycalculation.com

The LCM of 15 and 21 is 105.

- Find the prime factorization of 15

15 = 3 × 5 - Find the prime factorization of 21

21 = 3 × 7 - Multiply each factor the greater number of times it occurs in steps i) or ii) above to find the LCM:

LCM = 3 × 5 × 7 - LCM =
**105**

MathStep (Works offline)

Download our mobile app and learn how to find LCM of upto four numbers in your own time:

Android and iPhone/ iPad

Find least common multiple (LCM) of: 30 & 42 45 & 63 5 & 7 75 & 105 105 & 147 30 & 21 15 & 42 45 & 21 15 & 63 75 & 21 15 & 105 105 & 21 15 & 147

Enter two numbers separate by comma. To find least common multiple (LCM) of more than two numbers, click here.

© everydaycalculation.com