Redraw the nos. below in a conventional 9 by 9 frame of boxes. Usual rules apply. In the below x = a blank box
8 x x x x x x x x x x 3 6 x x x x x x 7 x x 9 x 2 x x x 5 x x x 7 x x x x x x x 4 5 7 x x x x x 1 x x x 3 x x x 1 x x x x 6 8 x x 8 5 x x x 1 x x 9 x x x x 4 x x