About “Zhoubi Suanjing”
The Zhoubi Suanjing is an ancient Chinese astronomical and mathematical work, known by many other names, most famous for its presentation of Chinese cosmology and a form of the Pythagorean theorem. It claims to present 246 problems worked out by the Duke of Zhou and members of his court, placing its composition in the 11th century BC, though its present form seems no earlier than the Eastern Han (25–220 AD). (Summary adapted from Wikipedia, CC BY-SA 4.0.)
Some summaries adapted from Wikipedia, CC BY-SA 4.0.