Personally, I think that to learn mathematics well, in addition to being familiar with the basic knowledge points in mathematics fields such as arithmetic, algebra, geometry and analysis, it is more important to master the knowledge points. When you encounter problems, you should be diligent in thinking and have the spirit of research. Interest is the best teacher! And you've learned it before, but you just forgot it. It's simple. Look at the math textbook or the catalogue of magazines or forums first, which may remind you of something. Then look at the impressive ones first, and make up the rest of the knowledge points in a proper amount every day, as far as possible step by step, and accumulate from shallow to deep, so that you will never forget! Hope to adopt