It is normal. There is a big leap in high school and junior high school. It's normal to feel confused when you do the problem. The concept of high school mathematics is simple, but the problems are difficult to do, especially in the later period. The so-called problems are actually composed of many simple motifs.

In fact, it's normal to find it difficult when you just entered high school. Just get used to it. Generally, high school mathematics can't be learned well by IQ alone. Be sure to listen in class, because some topics in high school mathematics are classic. These topics are generally taught by teachers as examples, and they are also the motif of the college entrance examination. I don't know the college entrance examination questions, but they are all changed from the mother questions, so the foundation is the key. There are different ways to treat different topics. Generally, people who learn well will know how to do it through thinking when they get a basic question, because they know what the test center of this question is.

In addition, it is not enough to be typical. If you want to learn well, you still have to do more questions. On the basis of having a motif, the number of questions can be expanded. You can see more and get used to it. No one I know who studies well does not do the problem, regardless of IQ. Of course, you can't always do it, but you should also learn to sum up. If you want to do a problem that you can't do, it's no use if you can do it.

Improve computing power. The direction of exams varies from place to place, but high school mathematics has a good knowledge of calculation, especially for some complex numbers.