Factorial

Free interactive math game: Factorial — 5! = 120. Part of the Probability category on MathKite.

Example problems

Taken from the generator that powers this exercise. A fresh set appears every time the page is opened, and the printable worksheet holds ten of them.

  1. 2! − 1! = ?
  2. 3! = ?
  3. 5! = ?
  4. 2! + 1! = ?

About this exercise

The factorial — the product of all whole numbers up to a given one.

How to solve it

Multiply from 1 up to the number. By convention zero factorial is 1.

Worked example

5 factorial is 1 x 2 x 3 x 4 x 5 = 120.

Common mistake

Underestimating how fast it grows. 10 factorial already passes three million.