I graduated from a key university, and I have also experienced the senior high school entrance examination and the college entrance examination. As the saying goes, "a good memory is not as good as a bad writing", so my advice is useful.

It's an example. This kind of thing is very useful if you think and understand examples while copying. If you only have one formula, copy it without thinking, hehe, it is only useful for practicing calligraphy. In short, it is more or less useful. Personal suggestion: the former should copy well, and the latter should save time to review and prepare for the exam.

Finally, I wish you progress in your study, get a good grade, go to a good high school and get into Tsinghua.