When I was a kid learning arithmetic the only visual aid I remember is flash cards. These were useful for memorizing single-digit addition and multiplication, but is memorization really the best ...

Check out this cool iPhone app from Japanese coder Kako-san. In many parts of Asia, the Abacus is still used today, mainly to teach maths, so Kako-san decided to make an abacus app for the iPhone.

FORT LEE — For 10 seconds, a series of 50 random three-digit numbers flashed on the screen. After another second, abacus master Jeonghee Lee announced she'd finished the mental addition, correctly ...