A Factorials Guide [Math, Algebra]
Hello. This short post is on factorials. (Prerequisites: Multiplication, Division and Fractions)
![](https://steemitimages.com/640x0/http://pad1.whstatic.com/images/thumb/7/78/Do-Factorials-Step-4.jpg/aid584590-v4-728px-Do-Factorials-Step-4.jpg)
To start, here are a few examples of factorials.
![](https://steemitimages.com/640x0/http://quicklatex.com/cache3/73/ql_ed594044d49ae79b525c436e30831073_l3.png)
As you can see, a factorial is a nice and compact way of expressing the multiplication of descending positive whole numbers (n = 1, 2, 3, ...). The exclamation mark does not mean that the number is screaming or yelling at you.
With factorials, the general case is:
![](https://steemitimages.com/640x0/http://quicklatex.com/cache3/e4/ql_d916f186fee44538efd6d38944a64ce4_l3.png)
An alternative version of factorials is in ascending order:
![](https://steemitimages.com/640x0/http://quicklatex.com/cache3/ae/ql_ec53fc2ca457f272b267c511889c28ae_l3.png)
Special factorial cases include 1! = 1 and 0! = 1.
Division With Factorials
You may encounter fractions with factorials in the numerator and in the denominator. Here are some examples.
Example One
![](https://steemitimages.com/640x0/http://quicklatex.com/cache3/bb/ql_8b2a6a4b41de214abbb046205d9ea9bb_l3.png)
Example Two
![](https://steemitimages.com/640x0/http://quicklatex.com/cache3/3c/ql_7a7da909539a502e42c7f6bda243ea3c_l3.png)
Example Three
![](https://steemitimages.com/640x0/http://quicklatex.com/cache3/70/ql_242e7bcb8c052afa4b62e03e3be79b70_l3.png)
Practice Problems
I have these practice problems all in one image file (Credit to QuickLaTeX.com).
Solutions
2400
2
2.5
4
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