Greatest Common Factor (GCF)

These free printable GCF worksheets are ideal for 5th and 6th graders learning to find the greatest common factor of two numbers - the exact skill used to simplify fractions to lowest terms.

How to Solve Factors & Multiples

List the factors of each number and take the largest one they share. For the GCF of 12 and 18: the factors of 12 are 1, 2, 3, 4, 6, 12 and the factors of 18 are 1, 2, 3, 6, 9, 18, so the GCF is 6. Shortcut: if one number divides the other evenly, the smaller number is the GCF.

You can view the preview of this worksheet below, or download the full high-resolution PDF along with the answer key for easy grading.