LESSON: Greatest Common Factors

READ: Find the Greatest Common Factor Using Lists

In this lesson, you will be learning about the greatest common factor (GCF). You can figure out what the GCF is by looking at the name.

What is the greatest common factor? The greatest common factor is the greatest factor that two or more numbers have in common.

One way to finding the GCF is to make lists of the factors for two numbers and then choose the greatest factor that the two factors have in common.

Example

Find the GCF for 12 and 16.

First, we list the factors of 12 and 16.

$&12 && 16\\ &12 \times 1 && 16 \times 1\\ &2 \times 6 && 8 \times 2\\ & \underline{4} \times 3 && \underline{4} \times 4$

Next, we can underline the GCF.

The GCF is 4.