Telling the truth, high school mathematics is difficult and practical. Its purpose is to examine/train your logical thinking ability, the ability to combine numbers with shapes, and a little abstract thinking. But solving problems and competitions can bring a sense of accomplishment. In addition, the contents involved in competition mathematics, such as differential integral fraction, are also the learning basis of science and engineering in universities (analogy pinyin is used for language learning and physical training is used for sports competitions). At that time, abstract thinking was the main thing, which is also the really interesting place of mathematics.