Junior high school mathematics is not particularly extensive, and it should include some basic formula simplification, probability, function and geometry, among which geometry and function account for a large proportion.
Personally, I think junior high school mathematics is not difficult. If you want to learn well in the senior high school entrance examination and get good grades, mastering knowledge is the foundation. What is more important and more difficult is the formation of a kind of thinking and the grasp of various problems. Junior high school mathematics should study more and do more problems, sum up the best rules and communicate with teachers more. If the teacher is kind and has more contact with the teacher, the teacher will help you solve many puzzles. Junior high school study is not too tense, nor too difficult. If you want to learn well, you must study hard. Moreover, the questions in the senior high school entrance examination are relatively fixed, so you can have enough time to solve the remaining problems in the review stage. Therefore, you should have a sense of urgency, but don't be too stressed.