Least Common Multiple (LCM)

This tutorial will explain what the least common multiple (LCM) is and how to find it.

Multiples


Multiples are numbers that result from multiplying numbers with integers (not fractions or decimals).

Example: The multiples of 3 are….

0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, etc..

The opposites of these numbers would be multiples as well.

multiples

Common Multiples


Multiples that are the same for 2 or more numbers.

For example 3 and 4.

Multiples of 3: 0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60 etc..

Multiples of 4: 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60 etc..

The common multiples are 12, 24, 36, 48, 60, etc.

The Least Common Multiple


The smallest common multiple of two or more numbers. In the example of 3 and4. 12 is the smallest shared multiple of 3 and 4, so 12 is the least common multiple (LCM).

There are two popular methods for finding LCM.

List Method:

LCM

Prime Factorization:

LCM Prime Factorization

Watch a Video Tutorial


Here is a video tutorial comparing fractions.

Interactive Class on this Topic


Take an interactive middle school math class on this material, click here

 

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