Calculator Soup
Calculator Soup: Greatest Common Factor Gcf Calculator
Calculate GCF, GCD, and HCF of a set of two or more numbers and see the work using factorization. An interactive calculator, explanations, and examples are included.
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.