Introduction to the famous mathematician in China: Hua (1910-1985), who worked until the last day, was born in a small businessman's family in Jintan County, Jiangsu Province. He likes math since he was a child and is very clever. One day, the teacher made a math problem: "I don't know what the number is today. Three or three counts leave two, five or five counts leave three, and seven or seven counts leave two." What is the geometry of things? " "23!" Teacher's.