PORTLAND, Ore. — Nearly two decades ago, Miwako Sakabayashi opened the doors to her Portland-area Japanese Abacus Math School. Today, Sensei Miwako continues to teach local kids how to tackle math ...

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 ...