I suggest that it is best not to use the "middle school textbook", which is harmful to learning mathematics and other sciences. I'm a freshman now, and I'm also poor at math and chemistry. Mathematics mainly depends on practicing more questions, and the understanding of teaching materials depends on oneself, not on lectures. Only by understanding and absorbing can we turn it into our own knowledge. I suggest you buy some classified chapter questions, divide the difficulty gradient types and do more exercises. It's not bad to buy a handbook of important and difficult points in chemistry. I have used it for several years. The above examples must be done before you look at them. Be sure to understand the classification of absorption. It's really good to suggest "postgraduate entrance examination" when you do the questions in senior three!