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Browse Middle School Factorials
Stars indicate particularly interesting answers or good places to begin browsing.

Selected answers to common questions:
    Table of factorials, 1!-30!

Given a Factorial, Find the Number [05/02/2003]
How can we find a number if the factorial is given?

Smallest Value of N!; Factorial Table [11/07/2001]
If N! ends in exactly 3 zeros, what is the smallest possible value of N?

What Is N Factorial Used For? [08/29/2001]
I have heard that it is used in probability, but what for, and how?

x Factorial and the Gamma Function [05/29/1998]
What is x! when x is 0, negative, or not a whole number?

Choosing 3 of 6 Colors [03/03/2000]
Patrick has a box of crayons with red, blue, yellow, orange, green and purple. How many different ways can Patrick select 3 colors?

Circumference of a Circle, Value of 5! [5/15/1996]
The area of a circle is 16 pi. What is the circumference of the circle? Also, what is the value of 5!?

Combinations of Coins [1/28/1996]
If I had 6 coins in my pocket, how many combinations could I have?

Decimal Places in Large Factorials [04/29/2003]
Is there an easy way to find how many decimal places or how many zeros the decimal notation of a large factorial number will have?

Derivative of x! [05/27/2003]
My Pre-Calculus teacher gave my class several derivative practice problems to do in our spare time, one of which is: (d/dx)(x!).

Double Factorial [02/22/2002]
Can you tell me what two ! marks mean in factorial questions?

Factorial [4/1/1996]
What is factorial?

Factorials [11/15/1994]
One day when I was playing on a calculator, I found that 1 and 0 both have a factorial of 1. Can you explain this?

Factorials [02/07/1998]
How do you find the number of zeros at the end of a number factorial? For example, 100! or 130!

Factorials [2/3/1996]
What does 3! mean?

Factorials and Order of Operations [09/21/2000]
Where do factorials go in the order of operations?

Factorials of Negative Integers [06/27/2002]
Is it possible to compute factorials for negative integers?

Find the Last Eight Digits of a Factorial [1/30/1996]
Find the last eight digits of 69! where 69!=69x68x67........x1

Given x!, Find x [12/21/2002]
If the value of x! is given, how do we find the value of x?

Googol Factorial [11/09/1996]
What is googol factorial?

How Big is a Googolplex? [05/29/2003]
Is there anything on Earth that is as big as a googolplex?

How to Evaluate 4!!!! [10/16/2003]
Our Calculus 2 teacher has challenged us to find the exact value for 4!!!!, but the number is too large to reasonably calculate by hand.

An Informal Argument for Why 0! = 1 [01/13/2008]
I don't understand why 0! equals 1. Can you explain it?

Odd Factorial [12/24/2001]
Can a factorial ever be odd?

Origin of the Factorial Symbol ! [01/14/2002]
My students would like to know the origin of the mathematical symbol for factorial - !.

Representing a Number [10/29/2001]
How can you represent the number three without using any letters or variables or the digits 1 through 9?

Six Billion Factorial [05/15/2003]
6 billion p 100. I know how to do permutations but there must be a quick way to do a problem like this.

Zero Factorial [05/24/1999]
Why does 0! = 1?

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