PlaySudoku.us
Hard · Puzzle #520
5
4
3
8
1
9
7
9
7
8
6
3
5
8
4
7
3
1
4
2
8
7
2
3
5
3
"In mathematics the art of asking questions is more valuable than solving problems." — Georg Cantor
"In mathematics the art of asking questions is more valuable than solving problems." — Georg Cantor
Sudoku became a global phenomenon in 2004 after The Times of London started publishing it daily.
Sudoku became a global phenomenon in 2004 after The Times of London started publishing it daily.