League matches are divided into one test and two tests. The initial test is basically the difficulty of the finale of the college entrance examination, but the time is tight and involves a small amount of extracurricular skills. Generally speaking, the four questions in the second exam are geometry, number theory, algebra and combination, and the difference will not be too big. According to the total score, the first, second and third prizes of the province will be awarded, and the top winners of the first prize of the province (about 3 to 10, depending on the situation of each province) can enter the provincial team; Members of the provincial team can represent their province in China Mathematical Olympics (CMO), referred to as winter camp, and can win gold, silver or bronze medals. Gold medal players and some silver medal players can enter the national training team. The national training team will conduct a selection examination and select six national players to participate in the international Olympic Games.

Personally, I think Orsay's classical geometry and combination are very good and basic, algebra is ok, and number theory is boring. If you want to win the first prize or join the provincial team, I recommend reading this set of books, especially number theory, combination, circle and others. This set of books is more difficult and has a certain foundation to read. When geometry is free, you can also look at modern European geometry to cultivate your sentiment. You can also brush it to IMO or middle school mathematics (brush it into a problem set). The domestic competition questions are generally difficult, and the questions for IMO are still very rich. That's how I brushed it. The key to the Olympic Games is to have one's own thoughts, experience and solutions, think more and master some necessary skills, but more importantly, the viewpoint, especially the difficulty viewpoint above the winter camp, is very important. That's all, I hope it will help you!