Still quite proud. When I was in college, I found a part-time tutor in a tutor center. I was huddled with a little girl in grade one. Her heart disease is math, so I have been focusing on making up math.

In the process of teaching the little girl, I gradually found out how happy it is to impart knowledge to others, especially to see the joy of solving the little girl's problems, which is really a sense of accomplishment.