The Permutations

The Permutations of N items is N!

What is a permutation in Math?

A Permutation is an ordered group of items.

How many permutations are there for 2 letters?

In other words, how many different ways can you arrange the two letters like AB? Remember: order matters

As an example, consider the permutations of the letters A and B. Just think about how many different ways you can arrange A and B. The key to a permutation is that order matters!!!!

• AB
• BA

As you can see, the only difference between our two permutations is the order. In our first one "AB," A is first and B is last. In the second one, "BA," all that we did was switch the order so that B goes first and A last.

If we add the letter C to our items. We now have a permutation of 3 items: the letters A, B and C.

As the tree diagram below illustrates, there are a total of 6 ways to arrange the letters A, B and C.

All possible arrangements of the three letters are :1) ABC 2) ACB 3) BCA 4) BAC  5) CAB  6) CBA