approximately 5th century Sunzi

孫子算經

"孫子算經" by approximately 5th century Sunzi is a mathematical treatise written between the 3rd and 5th centuries CE. This ancient Chinese work explores arithmetic methods, Diophantine equations, astronomy, and calendar development. Divided into three chapters, it provides the first detailed description of counting rod rules and their manipulation in basic operations. The treatise also contains the earliest known example of the Chinese remainder theorem, a fundamental tool for solving complex mathematical problems.