Cheng Dawei (1533 ~ 1606) was a businessman and inventor of abacus in Ming dynasty. Word Rusi, No.,Han nationality, Lingkou, Xiuning County, Anhui Province (now Tunxi, Huangshan City). When I was a teenager, I read widely and was very interested in calligraphy and mathematics. I have never been an official in my life. He has been doing business in the middle and lower reaches of the Yangtze River since he was 20 years old. Because of the need of business computing, he has been paying attention to mathematics, visiting famous teachers, collecting a large number of mathematics books, studying hard and sometimes gaining experience. When he was about 40 years old, he went home, devoted himself to research, referred to various theories and supplemented his own opinions. At the age of 60, he completed his masterpiece "The Unification of Pointing Algorithms" (referred to as "Algorithm Unification").