Difficult. The third subject of junior high school mathematics includes three sections: written test experience, case analysis and teaching plan design. During the inspection, we will choose a topic from the books of linear algebra, probability theory and advanced mathematics, and the scope is very wide. Topics are often students' mistakes, the causes of mistakes, the advantages and disadvantages of teachers' teaching behavior, mistakes, existing problems and countermeasures. The content is very flexible and difficult to grasp.