Test your math skills! Sum Points is relaxing, soft puzzle game with clear, simple rules. Forty one levels (or more?) will test your brain to the limit. Try to solve them all! Game objective is to set value of Target tiles to zero by placing Num tiles in right positions. Blue round Num tiles decrease value of Target tiles in a diagonal directions from the point they placed. Red square ones subtract values in horizontal and vertical directions.

http://armorgames.com/play/17710/sum-points