Fill the grid so every row, column, and 3×3 box has the digits 1–9 exactly once.
🎯 GoalFill every row, column, and 3×3 box with the digits 1–9. Each digit appears exactly once in each.
🎮 ControlsClick a cell, then type 1–9 (or tap a number button). Press Notes (or N) to leave small candidate marks. U undoes.
💡 TipScan for digits that can only go in one spot in a row, column, or box — those are your easy wins.
What students learnLogical elimination — proving what a cell must be, never guessing.
Try in classPair think-aloud on Easy. Exit ticket: explain one square you solved and how you knew.