PlaySudoku.us
Easy · Puzzle #253
8
3
1
2
4
7
9
6
5
2
7
4
3
8
1
1
2
5
9
2
9
6
8
5
4
4
5
6
1
2
1
7
5
3
6
3
5
2
9
1
8
9
1
4
5
6
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.