That looks like a completely different thing. The article seems to be about learning mental arithmetic tricks like (50+x)^2=(25+x)*100+x^2. https://apkpure.net/

That looks like a completely different thing. The article seems to be about learning mental arithmetic tricks like (50+x)^2=(25+x)*100+x^2. https://apkpure.net/zero-hero-math-calculation-pro/com.ankitkumar.maths_tricks_alpha https://apkpure.net/zero-hero-math-calculation-pro/com.ankit... for Android has a lot more tricks to learn and practice for free, but it seems to have been removed from the Play Store during the latest developer agreement update purge.