The goal is to color in some of the cells to satisfy the clues.
The number at the bottom of each column is the sum of the values of the black boxes of the numbers on the left. The number at the right of each row is the sum of the values of the black boxes of the numbers on the top.
Squares of Doom: Multiplication
Solve each of the 10 levels by filling in the gray squares to make the difference of the black squares, both rows and columns. Careful though: boxes can have a pair that must contain the same number. Give the game your best shot!