How to play Sudoku
The world's favourite number puzzle. No maths needed, just logic.
The rules
- Fill every empty square with a digit from 1 to 9.
- Each row must contain 1 to 9 exactly once.
- Each column must contain 1 to 9 exactly once.
- Each of the nine 3×3 boxes must contain 1 to 9 exactly once.
A quick example
This row already has every digit except 7, so the empty square must be 7.
Tips
- Start with the rows, columns and boxes that are nearly full. They have the fewest options.
- Pick a digit and scan the whole grid for it. Where can it still go in each box?
- Use Notes to pencil in candidates when a square could be one of two or three digits.
- When a digit can only go in one square of a row, column or box, it must go there, even if that square has other candidates. This is a hidden single.
- Stuck? A hint explains the reasoning behind the next step, so you learn the technique.
Most puzzles take 5 to 20 minutes.
Numalo is 28 number games for iPhone, iPad and Mac. Every puzzle is made on your device and proven to have exactly one answer. No ads, no subscription.