The aim of a Sudoku puzzle is to fill in the grid so that each row, each column and each box contains all the numbers from 1 to 9.
Usually, the grid is 9 squares by 9 squares, using the numbers from 1 to 9. Smaller grids will use the numbers 1 to 4 or 1 to 6.
Sometimes it is easy, but often it is fiendishly difficult. Try different strategies for yourself by just having a go!
There are three stages. Each stage is harder than the last. Can you complete all three stages? Click on the link below to give these a go!