First of all, analyze the papers that failed this exam. Since all mistakes are calculation errors, it means that you could have done it, not because you couldn't, but because you were careless.
If you want to solve the problem, the best way is to get into the habit of checking. You can roughly write the calculation process of each calculation step by step on the draft paper (not very detailed, of course, the examination time allows). After each test paper is finished, it should be carefully checked and corrected in time if there are any mistakes. It is a pity to make calculation mistakes in mathematics. Answer questions carefully at ordinary times and form a good habit of checking papers.
In addition, strengthen the knowledge points that you can't do, understand the knowledge points that you don't understand, and then assist a certain amount of the same type of questions to practice, so as to try to do similar questions in the future.
There are more than half a year before the college entrance examination, so don't panic yourself. It is normal to make two mistakes at a time. Be calm and don't be impatient when you do the test paper.
Usually, if you have the conditions, you can exchange inspection assignments with your classmates. You must take all the points you deserve for the questions you can do. If you can do it and lose points, you will regret your efforts.
Focus on your own problems, practice more, find the most prone to mistakes, and practice certain exercises.
Summarize after doing a set of questions each time, and then make targeted corrections.
Don't lose your temper if you don't come to the college entrance examination. According to your established study plan, step by step, slowly but surely.