Place the digits from 1 tot 9 in every row, column and 3x3-block. All horizontally and vertically neighboring digits with the sum 10 are marked with X, all horizontally and vertically neighboring digits with the sum 5 are marked with V.
Place the digits from 1 tot 9 in every row, column and 3x3-block. All horizontally and vertically neighboring digits with the sum 10 are marked with X, all horizontally and vertically neighboring digits with the sum 5 are marked with V.