What is the greatest common factor of 12 and 18?

To determine the greatest common factor (GCF) of two numbers, you need to identify the numbers that both can be evenly divided by and then select the largest of those common factors.

In the case of 12 and 18, you start by listing the factors of each number:

• The factors of 12 are: 1, 2, 3, 4, 6, and 12.

• The factors of 18 are: 1, 2, 3, 6, 9, and 18.

Next, you look for the numbers that appear in both lists, which are the common factors: 1, 2, 3, and 6. Among these common factors, the greatest one is 6.

This means that 6 is the highest number that divides both 12 and 18 without leaving a remainder. Therefore, the correct answer is 6, as it is the greatest common factor.