Advanced mathematics mainly focuses on calculus, which has little to do with high school knowledge. You don't have to worry about poor foundation, but you should look at high school mathematics first, because there is an introduction to high school knowledge before high school mathematics. Hehe, if you don't feel at ease, you can look for the advanced mathematics preview of Tongji University's fifth or sixth edition first, and you can also find courseware related to advanced mathematics online to help you learn. The knowledge in advanced mathematics is one.