PlaySudoku.us
Easy · Puzzle #91
4
2
9
5
6
8
3
1
3
8
4
2
7
9
6
9
8
3
7
5
7
6
4
2
9
1
6
7
3
8
5
3
1
6
5
7
2
5
2
3
8
4
3
4
6
9
5
7
9
5
2
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.