The 24 Game is deceptively simple: given four numbers, combine them with + , - , × , ÷ to make exactly 24. Sounds easy, right? Try solving 1, 5, 5, 5 — it stumps most people. I built a complete solver for my math puzzle platform, and the algorithm turned out to be a great exercise in combinatorics, expression trees, and floating-point traps. Let me walk you through it. The Problem Space Four numbers, four operators, and parentheses. How many possibilities? Permutations of 4 numbers: up to 24 (4!