Saturday, June 7, 2014

What are Least Common Multiples (LCM)


In our previous post, we talked about common multiples. Well, least common multiples or LCM is pretty much the same thing, except you just have to find the least common multiple. So, let's get started!

Least Common Multiple

In order to find the least common multiple of any numbers, you need to first know the times table of that number. However, if the number is large, you can always multiply to find its multiples!

Let's say that we have the numbers 12 and 18. Remember, we must first list its multiples:

12: 12,24,36,48,60,72,84,96,108,120,132,144,156,168,180,192,204,216,228,240
18: 18,36,54,72,90,108,126,144,162,180,198,216,234,252,270,284,306,324,342,360

As you can see, I have listed the first 20 multiples of both 12 and 18. Next, I will find all the common multiples and list them:

Common Multiples: 36, 72, 108, 144, 180, 216

The last step is simple: figure out the least common multiple!
The least common multiple is obviously 36.
Therefore, the LCM of 12 and 18 is 36.

 Sheet 1 Practice Problems on Finding Least Common Multiples

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