How To Calculate Combinations

In order to figure how many different combinations are possible in a set, you'll need to know how many options are available (n) and how many are used each turn (r). Next, you'll need to understand the expression "n!". If, for example, n is 5, then n! = 5*4*3*2*1, or 120. The formula you want to use is:
n!
C= -----------
r! * (n-r)!

Note that the (n-r)! in the denominator cancels out a portion of the numerator. This link will familiarize you with the terms and give examples: http://www.mathwords.com/c/combination_f...

To calculate combinations you must have a good knowledge of mathmatics. Some calculators you buy have this feature built in also. There are so many different kinds of combinations the possibilities are endless. For more information look here: http://www.mathsisfun.com/combinatorics/...;