How to Solve a Sudoku????

Easy

1. Use the counting principles to solve the puzzles. Since you already know that you can't have the same number in any row, column, or nine-square block, you can use that to help you get a number. The difficulty depends on the placement of the numbers given to you.
2. Seek "definites". When solving an easy Sudoku, the first thing you should do is look for definites. Definites are numbers that are definitely going to be there. Starting at 1, draw imaginary lines through boxes in that 1's row and/or column. When there is only one box left in the 3x3 box, you know that is a definite. (See images one and two).
3. Work your way through the numbers until 9. Since you have filled in some numbers, this should help get other numbers that had more than one possibility before. (See images three and four. Notice how the 3s could not have been solved before, but are solved in the final).
4. Look again when stuck. If you get stuck, go back and make sure to look at everything. It is almost guaranteed you missed something. That one number is usually all you need to get going again. If you still cannot find any solutions, start labeling every block with every number that could possibly go in that box. For example, in image one, all the empty boxes have numbers that could possibly go there. Fill these in. If there is a 1 in the row or column of that box, you know that 1 is not a possibility.
5. Start by doing Sudoku in the newspaper or online (see links below). The newspaper Sudokus are usually easier on Monday and Tuesday. The difficulty increases as the week passes.