Drexel dragonThe Math ForumDonate to the Math Forum

Ask Dr. Math - Questions and Answers from our Archives
_____________________________________________
Associated Topics || Dr. Math Home || Search Dr. Math
_____________________________________________

Factorials


Date: 2/3/96 at 22:20:17
From: Anonymous
Subject: 3!

What does 3! mean?  I've looked it up in my math book index about 40 
times,but I'm only in fourth grade, so I might not find it there. 


Date: 3/21/96 at 19:48:3
From: Doctor Ken
Subject: Re: 3!

Hello!

3! is a neat thing.  It's said "three factorial," and it means 
3 x 2 x 1.

Similarly, 7! (seven factorial) means 7 x 6 x 5 x 4 x 3 x 2 x 1.
And so on.

Here are a couple of other things about factorials: 1! = 1, which pretty
much makes sense.  What's more, 0! = 1, which is really wacky.  But I'm 
afraid it's just defined that way.

Thanks for the question!

-Doctor Ken,  The Math Forum

    
Associated Topics:
Elementary Definitions
Middle School Definitions
Middle School Factorials

Search the Dr. Math Library:


Find items containing (put spaces between keywords):
 
Click only once for faster results:

[ Choose "whole words" when searching for a word like age.]

all keywords, in any order at least one, that exact phrase
parts of words whole words

Submit your own question to Dr. Math

[Privacy Policy] [Terms of Use]

_____________________________________
Math Forum Home || Math Library || Quick Reference || Math Forum Search
_____________________________________

Ask Dr. MathTM
© 1994-2013 The Math Forum
http://mathforum.org/dr.math/