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Interactive
Handipoints Inc.

Factorials of Numbers

For Students 7th - 9th
For this factorial activity, students compute the factorial of a given number. This on-line activity provides 10 problems and is a self-checking activity.
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Website
Wolfram Research

Wolfram Math World: Factorial

For Students 9th - 10th
This page gives a very complete description of the use of factorials in mathematics. The most general information is at the top.