PlaySudoku.us
Easy · Puzzle #217
4
8
5
8
5
7
4
3
9
1
3
1
9
6
4
6
9
8
7
4
5
7
8
2
1
6
4
6
9
8
1
4
8
9
3
2
5
3
9
4
7
9
4
5
6
1
The hardest Sudoku puzzles require techniques equivalent to propositional logic — the same foundation used in computer proofs.
The hardest Sudoku puzzles require techniques equivalent to propositional logic — the same foundation used in computer proofs.
The hardest Sudoku puzzles require techniques equivalent to propositional logic — the same foundation used in computer proofs.
The hardest Sudoku puzzles require techniques equivalent to propositional logic — the same foundation used in computer proofs.