Interactive Practice
Find the number for the highlighted cell
Apply Technique
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Find the number for the highlighted cell:
Naked Single Technique
A Naked Single occurs when a cell has only one possible candidate remaining after checking its intersecting row, column, and 3x3 block.
Rules:
- Examine an empty cell and look at all numbers present in the same row.
- Look at all numbers present in the same vertical column.
- Look at all numbers present in the same 3x3 box.
- If 8 distinct digits (1 through 9) are already used, the cell must be the 9th remaining digit.
Hint
- Always scan rows and boxes with 7 or 8 numbers filled in first.
- Use pencil notes to confirm that exactly one candidate number fits.