For the practice of buying calculation questions, do more exercises, check the answers (first of all, check the answers by yourself, not directly copy the answers), draw the wrong questions, analyze the reasons for the mistakes and why they are wrong, and then find similar questions and practice again. Take out the wrong questions if you have nothing to do, and develop the good habit of reviewing in time. You can also try to use the wrong book, that is, copy the wrong questions you have done to the wrong book. Draw keywords and keywords when reviewing questions, which will help you find keywords. Improve your examination speed. You should form good study habits when you are still young, and you will benefit for life in the future.