Best Websites and Resources to Learn the Abacus at Home: Learning the Abacus at home is an amazing way to improve the concentration of children of their age. With the availability of online resources, ...
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 ...
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