8
5
6
4
2
7
2
1
5
5
6
4
6
8
9
3
3
6
1
2
2
7
6
1
3
6
2
4
7
6
7
1
7
3
8
4
1
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.