IB Math AA HL

1. What This Problem Is Testing

We have 4 distinct letters (M, A, T, H) and need to arrange all of them.

2. Step-by-Step Strategy

1. First letter: 4 choices
2. Second letter: 3 choices (one already picked)
3. Third letter: 2 choices
4. Fourth letter: 1 choice
5. Multiply: 4 × 3 × 2 × 1 = 4!

3. Key Equations / Setup

4! = 4 × 3 × 2 × 1 = 24

4. Strategy Shortcut

24 different arrangements

5. Mnemonic / Memory Trick

Using the Fundamental Counting Principle: For the first position, we have 4 choices. Once we pick one letter, 3 remain for the second position. Then 2 for the third, and 1 for the last.

6. Common Mistake to Avoid

n! (when arranging all n distinct objects)