- ➊ Write exactly one number from the given Range into some cells of the diagram so that a number occurs at most once in each row and each column.
- ➋ Blacken the remaining cells. The black cells separate the the rows and columns into groups of numbered cells.
- ➌ The numbers on the top and left edge of the diagram denote the sums of the numbers in these groups in order from left to tight and from top to bottom.