For math problems, we pay more attention to our feelings. We can't learn new knowledge by rote like Chinese. Similarly, when taking notes, it is also important to choose keywords. For the fourth grade mathematics, the book should highlight important conclusions or inferences, so it is effective to remember these words in preview and look at these conclusions in combination with the previous examples. In fact, previewing notes is a personal habit. You can use any method that suits you. There is no specific pattern.