Indigo Mental Club

Mental arithmetic is a technique for quick mental calculation. All rules, lessons and tricks of Abacus and Soroban on our channel. Indigo Mental Training Club

Mobile application
Google Play https://play.google.com/store/apps/details?id=com.indigomental.mobile
AppStore https://apps.apple.com/ua/app/indigo-math-abacus-for-kids/id6450366535