What is the greatest common factor (GCF) of 12 and 18?

To determine the greatest common factor (GCF) of 12 and 18, we start by finding the factors of each number.

The factors of 12 are:

1, 2, 3, 4, 6, 12.

The factors of 18 are:

1, 2, 3, 6, 9, 18.

Next, we identify the common factors between the two sets of factors, which are:

1, 2, 3, and 6.

Out of these common factors, the largest one is 6. Therefore, the greatest common factor of 12 and 18 is 6.

This makes the correct choice the one indicating that 6 is the GCF, as it is the highest number that divides both 12 and 18 without leaving a remainder. Understanding this concept not only helps in finding the GCF for these specific numbers but also provides a method for tackling similar problems in the future by focusing on factors and their commonalities.