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Moderate Tips & Guides- Method 3
To the right is an example of a partial Sudoku puzzle. Using only the given information, there is a way for you to locate the position of a "1" on the grid. Can you figure it out? Move your mouse over the puzzle to reveal the answer. The correct position will be highlighted in green.
Sudoku Puzzle

Step-by-Step Explanation:

1. Look at where the lowest "1" is located. You can't place a "1" in that column because there is already a "1" in that column. That column is darkened because a "1" can't go in that column.
Sudoku Puzzle
2. Look at the 3x3 block in the upper left corner. A "1" has to go somewhere in this box because of the rules. The "1" can't go in any of the darkened areas, and it obviously can't go in the boxes where the "2," "3," "4" and "5" are. This only leaves the two squares that are highlighted yellow.
Sudoku Puzzle
3. Look at the first row that has the three yellow highlighted squares. Since we know that one of these is a "1," a "1" can't be in any other part of that row. In addition, the second row can't have any additional "1"s because there is already a "1" in that row, and the column that is 3 spaces from the right can't have any additional "1"s because there is already a "1" in that column.  Those rows and columns are darkened because a "1" can't go in those rows and columns. Sudoku Puzzle
4. Look at the 3x3 block in the upper right corner. A "1" has to go somewhere in this box because of the rules. The "1" can't go in any of the darkened areas, and it obviously can't go in the boxes where the "6" is. This only leaves the square that is highlighted green. Sudoku Puzzle
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