1. Solid basic knowledge of mathematics: the topics of mathematical competitions often involve difficult mathematical concepts and theorems, so participants need to have solid basic knowledge of mathematics, including algebra, geometry, probability and so on.

2. Fast calculation ability: A lot of calculations are often needed in math competitions. Participants need to have fast and accurate calculation ability and be able to solve complex mathematical problems quickly.

3. Logical thinking ability: Problems in mathematical competitions often require contestants to make logical reasoning and analysis, so contestants need to have strong logical thinking ability and be able to use mathematical knowledge and methods flexibly to solve problems.

4. Problem-solving skills and strategies: There are often some special problem-solving skills and strategies in math competitions. Participants need to be familiar with and master these skills and strategies to solve problems efficiently in a limited time.

5. Ability to resist pressure and patience: Math contests often complete a certain number of questions in a limited time. Participants need to have strong pressure resistance and patience, and be able to keep calm and concentrate in a tense examination environment.

6. Teamwork: Some math competitions are held in the form of teams. Participants need to have good teamwork skills and be able to work closely with teammates to solve problems together.

In a word, participating in junior high school mathematics competition requires solid basic knowledge of mathematics, quick calculation ability, logical thinking ability, problem-solving skills and strategies, resistance to pressure and patience, and teamwork ability. Through continuous study and training, contestants can improve their level of mathematics competition.