Pro Tip

Scan rows, columns, and boxes for Hidden Singles: a digit that can only go in one cell within a house.

Pro Tip
✓ Completed! 👍
2
4
6
5
2
6
8
5
2
7
4
3
6
8
7
9
3
2
8
6
1
9
4
5
Math Insight

Sudoku is a constraint satisfaction problem — the same class of problems used in scheduling, circuit design, and AI planning.

Math Insight