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