? One day, Cheng Dawei stopped at Yingbin Inn to stay. He saw the one on the left of the inn, with scarlet brick walls, people coming and going, and eight or nine boys coming and going. They look a little similar. After a while, an old man was hugged, and Cheng Dawei wondered, "What is this? What happened? So lively? "
? When I asked in the inn, it turned out that the old man had celebrated his sixtieth birthday, and all his relatives and friends came to congratulate him. It is his nine sons who are crowding round. Some of these nine sons are in their thirties, and some are babies. Cheng Dawei wanted to inquire about the ages of his nine sons. The shopkeeper went behind the counter and said, "A grandfather has nine children. If you ask the date of birth, you never know that you will have to wait for three years, and the year of * * * is 200 years.
? A generation of mathematicians can't be stumped by a trivial matter. Cheng Dawei casually said, "Jiu-Er 1 1 year old, eight children 14 years old, seven children 17 years old, six children are 20 years old, five children are 23 years old, Si Er is 26 years old, three children are 29 years old, two children are 32 years old and the eldest son is 35 years old."