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 ...
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.
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