To many Americans, Japanese math students seem like computer-brained superhumans who effortlessly outscore their U.S. counterparts. The image may be exaggerated, but the challenge is real. So a growing number of American schools are adopting the latest Japanese import: Kumon Mathamatex, a math- teaching method developed by educator Toru Kumon to improve his own child's performance.
Unlike Japan's notorious juku cram schools, which concentrate on passing exams, the Kumon system seeks to increase speed and accuracy in calculation. Students compete not with others but with themselves, constantly striving to better their own scores. A student is given a series of graduated...