Explanation

A combination is an unordered selection of objects.

Formula:
nCr = n! / (r! (n − r)!)

Example:
Choose 2 from 3 → 3C2 = 3! / (2!1!) = 3

Quiz

1. Are combinations ordered?

2. Write the formula for combinations.

3. 5 choose 3 → 5C3 = ?

4. When to use combinations?

5. Does order matter?

Answer Key

1. No

2. nCr = n! / (r!(n − r)!)

3. 5! / (3!2!) = 120 / 12 = 10

4. When order does not matter

5. No