PlaySudoku.us
Easy · Puzzle #190
4
8
9
5
3
5
6
8
9
2
6
9
8
7
9
4
3
7
6
2
8
3
7
8
6
4
5
9
2
1
6
5
2
9
4
4
8
7
9
6
2
1
9
2
7
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.