Sudoku puzzles to crack your brain. Fill in all 81 squares, so that all rows, columns and blocks of 9 are all unique.
You can choose the level of difficulty you want. The more stars, the harder.
Sudoku puzzle explanation Sudoku is a diagram of nine by nine boxes in which the numbers from 1 to 9 must be entered. The diagram of 9x9 is again subdivided into a box of 3x3. A number from 1 to 9 must be entered in each box.
In order to solve the puzzle, the boxes must be filled in such a way that in each row, every column and each box of 3x3 the numbers 1 to 9 only occur once.
You do not have to be a clever head, just a little patience and logical reasoning is needed to solve the puzzle.