sentences:  The beginning of Châu's schooling was at an experimental elementary school that had been founded by the revolutionary pedagogue Hồ Ngọc Đại, but when his father returned from the Soviet Union with his doctoral degree, he decided that Châu would learn more in traditional schools and enrolled him in the "chuyên toán" (special classes for gifted students in mathematics) at the Trưng Vương Middle School.At age 15, Châu entered the special mathematics class at the High School for Gifted Students, Hanoi University of Science (Khối chuyên Tổng Hợp – Đại học Khoa Học Tự Nhiên Hà Nội), formerly known as the A0-class.In grades 11 and 12, Châu participated in the 29th and 30th International Mathematical Olympiads (IMO) and became the first Vietnamese student to win two IMO gold medals, of which the first one was won with a perfect score (42/42).