An anagram is a rearrangement of the letters of a word. How many anagrams does "CAT" have?
All 3 letters are distinct. Count = 3! = 6. (CAT, CTA, ACT, ATC, TAC, TCA)
If letters repeat, use the multiset formula. Example: "BOOK" has 4 letters (2 O's). Count = 4!/2! = 12.