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### Origin of the Factorial Symbol !

```
Date: 01/14/2002 at 06:44:04
From: Julia Kolb
Subject: Origin of mathematical symbol !

My students would like to know the origin of the mathematical symbol
for factorial - !.  Furthermore, was the symbol used as an exclamation
mark in writing before it was used as a mathematical symbol?
```

```
Date: 01/14/2002 at 07:19:52
From: Doctor Peterson
Subject: Re: Origin of mathematical symbol !

Hi, Julia.

The Dr. Math FAQ includes a link to

Earliest Uses of Mathematical Symbols
http://jeff560.tripod.com/mathsym.html

which is a great site to answer questions about the origin of math
symbols. If you look up "!" there (under "probability and
statistics"), you find that the symbol was used in place of an
earlier notation that was less convenient for printers. The
exclamation mark was already in use as punctuation, so printers did
not need to add a special symbol. (It sounds like what we do these
days using punctuation like "*" and "^" to avoid needing special
of symbols that already meant something:

In his article "Symbols" in the Penny Cyclopaedia (1842) De Morgan
complained: "Among the worst of barabarisms is that of introducing
symbols which are quite new in mathematical, but perfectly
understood in common, language. Writers have borrowed from the
Germans the abbreviation n! to signify 1.2.3.(n - 1).n, which
gives their pages the appearance of expressing surprise and
admiration that 2, 3, 4, &c. should be found in mathematical
results."

I have to admit I often feel the same way! (Symbolic pun not
intended.)

- Doctor Peterson, The Math Forum
http://mathforum.org/dr.math/
```
Associated Topics:
Middle School Factorials

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