First of all, there are many people like you, who get full marks in primary school mathematics, but make mistakes in junior high school one after another, and their grades are not satisfactory. There are two reasons for this: 1. You don't adapt to the new life in junior high school; 2. You are not careful enough.

For the above two points, my suggestions are:

1. Arrange the study time in a planned way every day, listen carefully in class, and ask questions when you have time (I have a classmate who is also a junior high school student and doesn't ask questions in class, so my grades have been good, especially in math. )

You can discuss this topic with several classmates after class. You can try to check a pair of homework answers with your classmates with good grades, find out your mistakes, and ask them for answers if you don't understand. You can look at the situation instead of the exam. )

3. Play when you should play, and study when you should study. Don't care too much about grades and rankings, but also need to decompress yourself appropriately. I just play when I should play and study when I should study. Sometimes when I am too tired, I will stop thinking and play computer. )

Prepare a wrong book, copy out the wrong questions and do it again. This is the advice given by our teacher. It is helpful to review before the exam.

5. When you encounter a wrong question, you should find out the cause of the error and correct it in time, and then correct it yourself or give it to the teacher.

6. You can ask your parents, friends, teachers and others for help.

PS: I have a senior. In primary school, it was 100. As a result, in junior high school, he got a math paper with a full score of 100. He got 14 and was beaten half to death by his mother. Later, he worked hard and never failed again. So it's normal to fail in the exam. Don't care too much.