I remember the headmaster of our time, who taught himself in the third grade. When he was in Grade Two, he taught himself all the courses in Grade Three. When he was in Grade Three, he did mock college entrance examination every day. Mathematics has never been lower than 140, 150. What a miracle! I remember that when we first entered the third year of senior high school, the math in the second year of senior high school was awesome, and it was normal for us to pass the first monthly exam in senior high school.