PlaySudoku.us
Easy · Puzzle #415
7
6
8
8
4
2
1
6
5
1
5
6
9
3
7
8
4
3
8
7
9
9
1
7
3
4
4
6
1
9
8
5
4
1
3
6
1
6
5
4
4
2
9
6
3
5
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.