Objective: Learn how factorial notation is used to count arrangements and compute products of positive integers.

Definition:[br]n! = n x (n - 1) x (n - 2) x (n - 3) x ...x 2 x 1 [br][br]Example: 3! = 3 x (3 - 1) x 1 = 6

This applet introduces factorial notation and allows students to practice calculating factorials through a multiple-choice question.[br][br]Teachers can use this activity to introduce factorial notation and counting principles. Students solve the factorial problem and then review the explanation to reinforce their understanding. [br][br]How to use Applet?[br][br]1. Read the definition of a factorial. [br]2. Study the worked example. [br]3. Solve the multiple-choice question. [br]4. Check the explanation to verify your answer.

Explanation: [br]The correct answer is C. 120[br]5! = 5 x 4 x 3 x 2 x 1= 120 [br]or [br]5! = 5 x (5 - 1) x (5 - 2) x (5 - 3) x 1 = 120