Soroban Ninja (air.com.SOH.SorobanNinja) on Google Play
Soroban Ninja, a tournament everyday for the japanese abacus' fans.Gradually progress in levels for addition, multiplication and division.keep up your rank. and practice everyday.Soroban Ninja is a math practice application using the Japanese abacus Soroban to teach kids how to Add, Subtract , Multiply and Divide. Soroban Ninja starts with 1 digit operation and accumulate gradually according to the student level to reach up to 9 digits operations and more. Soroban Ninja can be used starting from preschool and kindergarten where level 1 to 4 are oriented to this age. up to level 40 high school or more.the best practice is to use Soroban Ninja 15-30 min everyday.