Some people may look down on role models or after-school role models. It's too simple. Yes, it looks very simple, because they are just the foundation and the basic components that constitute the difficult topics in the future, so it should be very simple. If you want to challenge the future problems, you must firmly grasp the foundation and go deep into the soul, so that you can handle the future problems with ease.
How can we "master" these foundations? It is not enough to just do it, and it is not enough not to make a few mistakes. My opinion is: can you just answer these basic questions with your brain, without draft paper and words (not just listing formulas)? This really tests whether these foundations have penetrated into your soul! The foundation is solid (this is really solid, there is no water at all), and the difficult questions are completely hopeless. In a calm and worshipped atmosphere, interest in advanced mathematics arises spontaneously. ...