Permutations

Permutations - An arrangement of 'n' (number) objects taking all or some of the objects at a time where the order does matter.

Without Repetition:

            Formula:  nPr = n!/(n-r)!

n - The total number of items to choose from.
r - The number of items being chosen.

ex. a) How many ways can you order billiard balls numbered 1 to 16?
 b) How many ways can you order 5 different balls?


a)
An easy way to do it is insert [1],[6],[MATH], go over to the 'Probability' option and select option 4 so it will look like this on your calculator:

16!

Really all '!' is, is a short cut for going 16x15x14x13x12xx11x10x9x8x7x6x5x4x3x2x1
answer: 20922789888000 or 2.09x10¹³

b)
 You can use the formula nPr = n!/(n-r)! 
n=16
r=5                     =16!/(16-5)!
                           =16!/11!
                           =524160
or with your calculator you can take a shortcut by inserting "16" then [MATH] button, over to probability and select option 2 "nPr"than insert the number "5". It should look like this on your calculator.

16 nPr 5

Hit solve and you should get the same answer as above: "524160".