All mines found
When a number has all its mines flagged, the rest of its cells are safe.
A 2 with two flags next to it has found both its mines. It cannot have a third, so every other hidden cell around it is safe to open. This is the move you make most often in Minesweeper, and the flags are what make it easy to see.
How it works
The highlighted number already has as many flags around it (yellow) as it shows.
Your turn
Each board is a real position from a game. Tap or click to open; right-click, long-press or switch on Flag to place a flag. If you are not sure, take a hint: the first one only shows where to look.
Which hidden cells can you be sure of?
How the exercises were chosen
A computer checked every board: in what you see, the only cells one number can prove are next to a number whose mines are all flagged, and these are exactly the cells you open.