Liu Hui 劉徽 was a Chinese mathematician who lived in the 200s. In 263 he published a book with solutions to mathematical problems presented in the famous Chinese book of mathematics known as Jiuzhang Suanshu or The Nine Chapters on the Mathematical Art.

In these commentaries he presented:

• an estimate of π to 3.141014 and suggested that 3.14 was a good approximation
• Gaussian elimination
• Cavalieri's principle to find the volume of cylinder

He also presented, in a separate appendix called Haidao suanjing or The Sea Island Mathematical Manual , several problems related to surveying.