I remember when I was in college, our math teacher was very handsome and good at math. Just ask him. Nothing is difficult. Later, after understanding, I learned that he graduated from the Institute of Physical Education and found someone to be a teacher at school through relationships. We were all shocked at that time. I am an old cow of advanced mathematics. For so many years, I really haven't met a better teacher than him, including my son's teacher. Our PE teacher was directly promoted to a math teacher, so the PE teacher is not good at math. This is a false proposition.