Fill in the numbers 1 through n in every row and in every column. Next to the puzzle the value of n is given. Numbers indicate the sum, the product, the difference or the result of the division of all the numbers in that region. Often the operator used is given. Subtraction and division can only apply to regions with two numbers. It is possible for numbers to occur more than once within a region as long as this does not violate any of the rules. More information.