What is the oldest surviving mathematical text?

The Zhou Thigh Calculating Classic, formerly known as Zhou Thigh, is one of the ten books of calculating classics, which is the oldest astronomical and mathematical work in China. It was written in the 1st century B.C., mainly clarifying the Gaitian theory and the four-point calendar at that time. At the beginning of the Tang Dynasty, it was stipulated as one of the teaching materials for the Ming Calculation Section of the State Zi Supervisory Board, and was therefore renamed Zhou Thigh Calculation Scripture.

The main mathematical achievement of the Zhou Thigh Calculating Scripture was the introduction and proof of the collinearity theorem.

The Zhou Thigh Calculating Classic adopts the simplest and most feasible method to determine the astronomical calendar, reveals the operation law of the sun, moon and stars, and encompasses the change of seasons, climate change, the north and south poles, and the reasoning of day and night. To the later life and work to provide a strong guarantee, since then successive generations of mathematicians do not take the "Zhou Thigh Calculating Scripture" as a reference, on the basis of continuous innovation and development.