# Counting Permutations

Dylan | Jul 22, 2019

This post will answer the following questions and provide examples:

- What are permutations?
- Why are permutations important?
- How can we calculate the total number of permutations?
- How can we calculate the possible permutations of a subset?

### What is a Permutation?

Simply put, a permutation is a unique ordering of a set or subset of data. Imagine the following set of 4 people:

Imagine the four individuals above are standing in a line. What’s another way the four people could be arranged to create a new and unique line? Perhaps Bob and Joe could switch places:

This arrangement is an example of one possible permutation (unique ordering) of the dataset.

### Finding the Number of Possible Permutations

What you’ll find with this calculation is that the remaining unused choices, 2 and 1 in our example are canceled out.

### Conclusion

I hope this brief introduction to permutations and the factorial function has been insightful! As always, if anything was left unclear or you have any remaining questions please ask in the comments below and I’ll try my best to provide a helpful response! Thanks for reading and happy permuting.