Substraction contest

Participate in the substraction contest. Get the fastest time and compete with your friends on Facebook, Twitter and other social networks to see who is the fastest in the art of substracting.Have 3 difficulty levels and each level will be more difficult operations.Join the fun game of substracting and exercise your mind.Ideal also for people who for various reasons have to exercise your mind. Do not let your brain atrophy and put them up.