Least Common Multiple

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Least Common Multiple: Learn

The Least Common Multiple (LCM) is the smallest number that two or more numbers will divide into evenly.

For a single number it is easy to find multiples by simply multiplying the number by increasing whole numbers (or, more simply "counting by" that number).

Example: multiples of 4 are 4, 8, 12, 16, 20, 24, and so on.

There are two good ways to find the Least Common Multiple of two numbers. Here's the first way:

Find the Greatest Common Factor (GCF) of the numbers
Multiply the numbers together
Divide the product of the numbers by the GCF.

An an example of this method, consider the numbers 15 and 12. Their GCF is 3, so the LCM is 15*12÷3 = 180÷3 = 60.

Alternatively, you could begin counting by the larger number until you reach a multiple which is also a multiple of the smaller number.

For example, again consider 15 and 12. Fifteen is the larger number, so start counting by fifteens:
15 - no, not a multiple of 12
30 - no, not a multiple of 12
45 - no, not a multiple of 12
60 - yes, 12*5=60 so 60 is the LCM.

LCM: Practice

What is the LCM of the two numbers?

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The LCM of and is:

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Game Name	Description	Best Score
	How many correct answers can you get in 60 seconds?	0
	Extra time is awarded for each correct answer. Play longer by getting more correct.	0
	How fast can you get 20 more correct answers than wrong answers?	999