What grade are you in? If you are in primary school or junior high school, you don't do well in the exam because you have a poor foundation and don't study hard. If it is a high school, it is normal to do well in the adaptation stage of senior one and senior two. Correct your study habits, don't be as careless as junior high school, do more problems and listen carefully in class, because the math difficulty of senior one comes up. If you don't do well in the exam, you must make it up!