Less than 90 points. No.1 teaching assistant is suitable for less than 90 points. One number teaching aid is a highly recommended high school basic mathematics tutorial book, which covers all the knowledge points of high school mathematics, including mathematical analysis, geometry, algebra and probability statistics. The content of this book is easy to understand and pays attention to detailed explanation. It is very suitable for beginners to learn and review high school mathematics, and help students who don't get 90 points in mathematics to improve their grades.