To learn how to solve sudoku puzzles, you can follow these steps (below we will look at an example from the pictures):
1. Start by understanding the rules of sudoku:- A standard sudoku grid consists of 9 rows and 9 columns, divided into 9 smaller 3x3 boxes.
- The grid will have some numbers pre-filled, called "givens".
- The goal is to fill in the remaining empty cells with numbers from 1 to 9, ensuring that each number appears only once in each row, column, and 3x3 box.
2. Look for obvious/forced numbers:- Begin by examining each row, column, and 3x3 box to locate any numbers that appear only once.
- Fill in these numbers as they are confirmed, as they will help eliminate possibilities in other cells.
3. Use the elimination technique:- Look for cells where only one number can fit based on the numbers already placed in the same row, column, or 3x3 box.
- Cross out and eliminate the numbers that cannot go in those cells.
- Repeat this process until no more numbers can be determined by elimination alone.
4. Apply the "only choice" technique:- Look for cells where only one number can be placed based on the numbers already in the same row, column, or 3x3 box.
- Fill in these numbers, as they are the only choices available.
5. Try the "what-if" technique (if necessary):- If the puzzle becomes too challenging to solve using elimination and the only choice techniques, try making logical assumptions or guesses.
- Choose a cell with a limited number of possible candidates and make an assumption.
- Continue solving the puzzle based on that assumption and see if it leads to a contradiction.
- If the assumption leads to a contradiction (e.g., two or more cells with the same number in a row, column, or 3x3 box), it is incorrect, and you can backtrack to the last correct state and try a different assumption.
- If the assumption leads to a solution without contradictions, continue solving the puzzle.