Chisanbop
Chisanbop or chisenbop (from Korean chi (ji) finger + sanpŏp (sanbeop) calculation 지산법/指算法), sometimes called Fingermath, is an abacus-like finger counting method used to perform basic mathematical operations. According to The Complete Book of Chisanbop by Hang Young Pai, chisanbop was created in the 1940s in Korea by Sung Jin Pai and revised by his son Hang Young Pai, who brought the system to the United States in 1977. With the chisanbop method it is possible to display all numbers from 0 to 99 on two hands, and to perform the addition, subtraction, multiplication and division of numbers. The system has been described as being easier to use than a physical abacus for students with visual impairments. (Wikipedia).
