Personally, I think it's okay not to. At least I don't need it, and I'm good at math. But it varies from person to person. Some people naturally like organization, while others don't. Look at personal preferences.

Then, I am in favor of summing up the problems that have taken too much time. I spent a lot of time, but I didn't finish reading it. I think someone cut out the wrong questions on the test paper and pasted them on the book. Although this saves time, it greatly affects the reading effect.

I wonder what grade you are in now.

The following is my personal experience:

No matter junior high school or senior high school, there is no need to do this in the first year. In the second year, we should start to sort out mathematical ideas and cultivate mathematical literacy. What is sorted out is not the problem, but the idea, the idea of thinking about the problem, all kinds of ideas, ideas, methods and so on. If you understand this thing, there is nothing that you can't learn math. The score can also be maintained at a high level.

To achieve this state, some people rely on the sea, while others rely on inscriptions. So it still varies from person to person. Don't be lazy at this stage. People who write about the sea naturally have feelings about these things (mainly ideas), while people who write classics should think a lot, find similarities between problems, and grasp ideas in this way.

So the core content is:

1, the preparation of the wrong question book varies from person to person.

2. Prepare a notebook to record the experience and thoughts of doing something wrong, and read it once in a while. I often think about this basic idea when I do problems (but don't be imprisoned)