PlaySudoku.us
Hard · Puzzle #371
7
6
3
9
1
1
3
6
7
2
6
4
8
5
3
8
1
6
4
2
3
8
6
7
4
1
2
9
Set theory provides the formal foundation for Sudoku's rules: each digit must appear exactly once per set.
Set theory provides the formal foundation for Sudoku's rules: each digit must appear exactly once per set.
"The important achievement of Apollo was demonstrating that humanity is not forever chained to this planet." — Neil Armstrong
"The important achievement of Apollo was demonstrating that humanity is not forever chained to this planet." — Neil Armstrong