A bit too random for me. It didn't really feel like it was worth the time I spent trying to figure out the sums because there was often no good solution and it was just a matter of figuring out how to loose the slowest. My main paint of feedback on how to improve it would be to make it more of a puzzle game with solutions. Then I would feel smart when I got a low score or even a perfect score and would be more inclined to play for longer.