How do you solve math permutations?

A permutation is the rearrangement of objects or symbols into distinguishable sequences.

You can use the formulas. nPr=n! / (n-r)!

where n the set from which elements are permuted and r is the size of each permutation (! is the factorial operator)

For example: How many ways can you rearrange the Word math? 4P4=4!/(4-4)! 4P4=4!/1 4P4=24