How to Play
The 24 Game gives you four numbers and one goal: combine them with basic arithmetic to reach exactly 24. You must use each number exactly once, in any order, with any combination of +, -, ×, ÷ and parentheses.
- Four card numbers appear on screen (each between 1 and 9).
- Click a number card to add it to your expression.
- Click an operator (+, -, ×, ÷) to add it.
- Use ( ) buttons to add parentheses for grouping.
- Click "= Evaluate" to check if your expression equals 24.
- All four numbers must be used exactly once.
- If you're stuck, click "Give Up" to see one valid solution.
Strategies & Tips
- Think in factors: 24 = 3×8 = 4×6 = 2×12 = 1×24. Try to make one of these pairs from two of the cards, then reach 1 with the other two.
- Division is key: Division can reach surprising numbers. If you have an 8, try 8÷(something) to create a useful fraction.
- Try reversal: If (a+b)×c doesn't work, try a×(b+c) or (a×b)+c.
- Use parentheses aggressively: Many solutions require non-obvious groupings. Don't hesitate to nest parentheses.
- Backspace freely: You can remove the last token at any time and try a different path.
FAQ
Are all card sets solvable?
Yes — every card set in this game has been verified to have at least one solution. The game uses a pre-verified list of 50 solvable sets, so you'll never be given an impossible puzzle.
How is the expression evaluated?
The game uses a custom recursive descent parser — no JavaScript eval(). This is safer and handles operator precedence and parentheses correctly.
What is the streak counter?
The streak counts consecutive puzzles you've solved. Clicking "Give Up" resets your streak to zero. Your best streak is saved in localStorage.
Can I use a number more than once?
No — each of the four card numbers must be used exactly once. Once you click a card, it dims and cannot be clicked again until you clear or backspace past it.