To get full marks on a math exam paper, study all the content you expect to encounter on the exam and improve your math skills as a whole. You can improve math skills by practicing and working with others to understand concepts rather than just memorizing content.
Getting perfect marks on any exam starts with learning all the content to be covered on the test. Take notes during lectures or classes and review them periodically before the test, rather than on the night before. Work on lots of practice questions. Draw up a schedule before the exam, allotting at least a few hours a day for each concept. Do practice questions for one concept every day. Depending on the exam paper, the question types can be predicted. On a standardized test, find online guides to help with question types, and on a school exam, review old tests to understand the types of questions being asked.
Another way to get perfect marks on a math exam is to be confident about your math skills before the test. Try to understand all math ideas conceptually, and then practice them in different situations. Finally, be calm on the day of the exam. If you have studied all the content and practiced hard, you can achieve a good grade.