It depends on when and for what purpose. Generally speaking, there is accumulation at ordinary times, that is, doing problems at ordinary times. Even if there was no problem at that time, I still learned through various channels. Then, in order to save the time before the exam, you usually use the method you said, which often gets twice the result with half the effort. If you don't do the problem at ordinary times, you will find the answer temporarily and understand it. It will also have a certain effect, but it will not be too big. Because learning mathematics, just watching and not practicing, will not improve! Take the high number you said. You may have memorized the integral formula, or you may have memorized it, but if you haven't been trained to solve problems (even if you can understand the answers, you can understand other people's explanations), I'm afraid you won't do it after you write the questions, especially if you encounter some slightly complicated questions. As some students said, teachers can understand what they say in class, but they won't do it when they get the questions. The reason is that they are not trained enough! Learning mathematics, understanding concepts, formulas, laws and theorems is more about experience and familiarity in application!