Drop Sum is a challenging skill game on www.flash-games.net for free. The goal for you is to drop tiles making columns and rows adding up to the required value. Only adjacent tiles with no gaps count. The more tiles you used to reach the required value, the more points you will get. There are four states for tiles. When the state is in red, three groups have been made to be ready to explode. In the game, you also should collect the stars which will give you a bonus. Come on and try to challenge this difficult game!