7
6
4
5
1
7
9
6
2
3
5
1
4
5
9
2
7
6
1
8
7
3
5
7
6
5
2
9
1
4
8
3
At peak Sudoku popularity in 2006, over 600 different Sudoku books were published in a single year.
At peak Sudoku popularity in 2006, over 600 different Sudoku books were published in a single year.
At peak Sudoku popularity in 2006, over 600 different Sudoku books were published in a single year.
At peak Sudoku popularity in 2006, over 600 different Sudoku books were published in a single year.