Instructions
Examine the numbers that already exist in your Sudoku grid. These numbers are the ones that you cannot change, and you must use these numbers to fill in the rest of the grid.
Fill in each of the nine boxes in each column of your Sudoku grid. Each column must have the numbers 1 through 9. Each of these numbers can appear only one time in each column. They can be written in any order. Use a pencil, as you will likely have to erase and rearrange numbers as you play.
Look at the numbers in each row of your Sudoku grid. Just like the columns, each row must have the numbers 1 through 9. Each of these numbers can only appear one time in each row. They can be written in any order. Erase numbers from boxes as needed until the numbers 1 through 9 appear only one time in each row and each column of your grid.
Examine the bold squares laid out over your Sudoku grid. Each square consists of three columns and three rows of three boxes each. There are typically nine different squares in a Sudoku puzzle. Each square must have the numbers 1 through 9, and each number in that sequence can appear only one time per square.