Soft Schools
Soft Schools: Greatest Common Factor Worksheet
Find the greatest common factor between two numbers. You may set the total number of problems per page, the minimum and maximum numbers, and an answer key is optional.
Topmarks Online
Topmarks: Multiples and Factors
A multiple-choice game with two game modes. In the first, you need to identify the Lowest Common Multiple and in the second the Highest Common Factor. Questions increase in difficulty depending on accuracy.
Math Slice
Math Slice: Greatest Common Divisor (Factor): Math Worksheets
This tool allows you to create worksheets where students must find the greatest common factor in a set of two to four whole numbers.