Greatest Common Factor (GCF) and Least Common Multiple (LCM)

Now we're going to use what we learned about factors text annotation indicator to find the Greatest Common Factor and Least Common Multiple . A common factor is a number that is a factor of two or more numbers.

The greatest common factor (GCF) is the largest number that divides evenly into the given numbers.

Here's an example.

We will show you how to use factor trees to figure this out for larger numbers where the answer is not so easy to find.

Let's look at an example.

Now let's take a closer look at GCF and LCM.

Question: What two numbers are NEITHER prime nor composite?

Answer: 0 and 1

NOTE: For the following examples, the answers don't work correctly when it gets to problems 1-3. You can find those answers below the video.

Problem 1's Answer: Prime Factorization of 11 is 1x11

Problem 2's Answer: Prime Factorization of 9 is 3x3

Problem 3's Answer: Prime Factorization of 45 is 3x3x5

Click HERE to learn more about solving word problems.

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