Poor grades and poor memory do not mean that you have become benzene. This talent is acquired. Mathematics is really difficult, but you should be interested in it first, so that you can go to class with the desire to learn, and you will find that you are much more serious in class than before (it is effective to listen to the teacher attentively in class). Secondly, you should finish your homework carefully. When you write your homework, you should try your best to write it well and think hard. But if you want to write it correctly, you have to concentrate on it in class, right? In addition, in the case of stable foundation, try to buy some difficult topics to do (synchronous with textbooks); If you feel that the foundation is not good, you can buy simple synchronous exercises to do it and lay a good foundation. This is the key. You can also buy synchronous explanations. I suggest you take it out after learning or after class, and draw key knowledge points with different colors. Personally, I think the textbook is well understood.
Memory takes a long time to practice. I suggest you buy some beautiful prose poems or short poems (that is, try to recite them once a day or a few days, and then recite them again in a few days, but you should review what you recited last time before reciting them. Over time, maybe your memory will improve, which will help your writing, but you should be patient and persistent, but you just don't know it.
But this is just my learning method, I hope it will help you!