Khan Academy
Khan Academy: Calculating Factorials (Practice)
This is a 7-problem quiz/practice on calculating factorials.
Varsity Tutors
Varsity Tutors: Hotmath: Graphing Calculator Practice: Discrete Mathematics and Probability
Practice using your graphing calculator for factorial, combination, and permutation expressions. If you get stumped or if you would like to check your work, then select the View Solution button, which is located directly under each problem.
CK-12 Foundation
Ck 12: Permutations and Combinations Compared Grades 9 10
[Free Registration/Login may be required to access all resource tools.] Given a set, learn how to calculate its number of permutations.
CK-12 Foundation
Ck 12: Probability: Permutations Grades 9 10
[Free Registration/Login may be required to access all resource tools.] Given a set, learn how to calculate its number of permutations.