Thank you for inviting me. At least you need to have a good knowledge of high school mathematics and dabble in competition content. If you can't explain this kind of thing clearly, don't make random reference. If a coach brings students to the competition, you can ask him to judge. The competition forms include preliminary competition, provincial semi-finals, national finals, national training team and world Olympics. There are other competitions to choose from. The content of specific questions is introduced in detail on the Internet.