Explanation

A permutation is an ordered arrangement of objects.

Formula:
nPr = n! / (n − r)!

• n = total objects

• r = objects chosen

Example:
3 people, arrange 2 → 3P2 = 3! / (3 − 2)! = 6

Quiz

1. Are permutations ordered or unordered?

2. Write the formula for permutations.

3. 5 objects, choose 3 → 5P3 = ?

4. What does “!” mean?

5. Does order matter?

Answer Key

1. Ordered

2. nPr = n! / (n − r)!

3. 5! / 2! = 120 / 2 = 60

4. Factorial (multiply all positive integers ≤ number)

5. Yes