Lee Jeonghee

Lee Jeonghee (; born 23 February 1963) is a South Korean abacus master. She is the only known soroban abacus master to have reached the eleventh dan. She is also known as Abacus Master (주산왕) in South Korea.

Biography Lee began training with the soroban abacus in fifth grade. In her first year of high school, she obtained the 11th dan. In 2007, Lee opened up an abacus training academy in Korea, where she has taught thousands of students, some of whom travel to the country solely to participate.

In 2001, Lee represented South Korea in the 20th International Abacus Competition and finished in first place in the singles category. Her students, selected for the program after their parents described them as distracted and underachieving in school, displayed significant improvement in mental calculation skills, as well as in focus and attention. By the end of the program, almost all of the students were able to mentally solve an addition problem of fifteen 5-digit numbers in under thirty seconds. During the episode, she demonstrated her ability to do Flash Anzan, adding together a total of fifty 4-digit numbers individually flashed on a screen for less than one second each, while simultaneously being interviewed by the hosts. During the same episode, she mentally added fifty 25-digit numbers in 94 seconds.

She has been a resident of Fort Lee, New Jersey.