Every Calcudoku has a single solution that can be reached logically. Fill in the grid such that no two digits repeat in any column or row. Use the shapes in the grid as your guide. Each shape contains a number equaling the product of the shapes' digits.
In the solution above, the top left shape has two digits 3 + 1 = 4. The bottom left shape has two digits 3 − 2 = 1.