Mathematics is mainly about memorizing formulas and then applying them. You write down all the formulas, and when you are free, look at more examples to see how to solve them. Basically, the questions in junior high school are similar, so it won't be difficult. You should take a good look at all the questions you made wrong before and write them down to consolidate them, so that the questions you have done will not be so easy to make mistakes next time.

Actually, mathematics is quite simple. You can learn it as long as you listen carefully in class. Have confidence ~ ~ ~