Permutation Calculator — Formule
## How to Calculate Permutations
### Formula
**P(n, r) = n! / (n - r)!**
Where:
- **n** = total number of items
- **r** = number of items being chosen
- **!** = factorial
Permutations count arrangements where **order matters**.
### Formula
**P(n, r) = n! / (n - r)!**
Where:
- **n** = total number of items
- **r** = number of items being chosen
- **!** = factorial
Permutations count arrangements where **order matters**.
Exemple Résolu
How many ways can you arrange 3 items from a set of 10? (Order matters)
- P(10, 3) = 10! / (10-3)!
- = 10! / 7!
- = 10 × 9 × 8
- = 720