| Wu Jing | |
| Nationality: | Ming |
| Occupation: | Accountant, mathematician, writer |
| Notable Works: | Jiuzhang Suanfa Bilei Daquan (1450) |
| Birth Place: | Hangzhou, Zhejiang |
Wu Jing (15th century), courtesy name Xinmin (Chinese: 信民), art name Zhu Yi Weng (Chinese: 主一翁), was a Chinese accountant, mathematician, and writer of the Ming dynasty who in 1450 published the arithmetic treatise Jiuzhang Suanfa Bilei Daquan (Chinese: 九章算法比類大全, "Complete Description of the Nine Chapters on Arithmetical Techniques").[1]
According to the 1488 foreword to Wu Jing's book written by Xiang Qi (Chinese: 項麒), a Ministry of Justice administrator who also hailed from Renhe (Chinese: 仁和, modern Hangzhou), Wu apparently worked as an accountant for several local officials and had a hand on the census, land surveys, and taxations of Zhejiang province.[2]
Jiuzhang Suanfa Bilei Daquan originally contained nine chapters excluding the "table of contents" chapter. After a fire destroyed many printing woodblocks, Wu Jing's grandson Wu Ne (Chinese: 吳訥) added some materials as he prepared the manuscript for re-printing. Currently, there are at least four extant copies from the Ming dynasty, housed separately in four libraries in Beijing and Shanghai.[3]
Every chapter begins with a topic from an "ancient" mathematical book, followed by Wu Jing's explanation of how real-life problems are solved with arithmetics.[4] For example, in the first chapter, "Land" (Chinese: 方田), Wu described how to approximate land areas of different shapes and included 214 problems.[5]
Because he was concerned with real-life problems, Wu Jing often preferred approximations over exact solutions.[6] The Ming-period mathematician Cheng Dawei criticized Wu's work as "disorganized and containing numerous mistakes" in his Suanfa tongzong (1592). The Qing-period scholar Mei Wending, however, considered Wu's work superior to Suanfa tongzong.[7]
Wu did not come up with new ways of solving older problems; he did, however, invent new methods of using the abacus.[8] He also proposed using colors and visualization to solve math (especially geometric) problems, which may have influenced Chinese cartography.[9]
The modern mathematician Qian Baocong noticed several identical arithmetic methods in Wu's work and the slightly later Treviso Arithmetic (1478).[10]