What is the Least Common Multiple?

Least Common Multiple

Least Common Multiple

The least common multiple, or LCM, of two numbers is the smallest value divisible by both the numbers. Or it’s the smallest number that both of your numbers divide into evenly.

The LCM can be found by finding the GCF, or greatest common factors, and the remaining factors. The LCM is the product of the GCF and those remaining factors.

For example, if we wanted to find the LCM of 18 and 30, we would first need to factor them. 18 is 2 times 9, since 9 is not prime we would factor 9 to 3 times 3. 30 is also even so we’ll start with 2. 30 is 2 times 15, 15 is not prime so we factor 15, 15 is 3 times 5.

The GCF, or greatest common factor, is 2 times 3, or 6. Our least common multiple is the product of our GCF, 6, and the remaining factors. The remaining factors are 3 and 5. 6 times 3, times 5. 6 times 5 is 30, 30 times 3 is 90. The smallest number that 18 and 30 will both divide into evenly is 90.



by Mometrix Test Preparation | Last Updated: May 15, 2019