Qin Jiushao, Chinese mathematician and text writer
Qin Jiushao was born in Sichuan province in 1202. His great opus, Mathematical Treatise in Nine Sections, cast light on extracting positive and negative roots, among other things.
Author of a method of solving the Chinese Remainder Theorem, he also discovered what Europeans called the "Ruffini-Horner method" of solving polynomial equations about six hundred years before they did.