PlaySudoku.us
Evil · Puzzle #75
3
9
1
2
5
7
9
6
2
9
4
5
6
1
6
4
6
7
3
8
4
2
6
3
1
"The only way to learn mathematics is to do mathematics." — Paul Halmos
"The only way to learn mathematics is to do mathematics." — Paul Halmos
Competitive Sudoku solvers can hold the full pencil-mark state of a 9×9 grid in working memory, updating it mentally as they go.
Competitive Sudoku solvers can hold the full pencil-mark state of a 9×9 grid in working memory, updating it mentally as they go.