It is good to refine the mathematics of Beijing Normal University in class. According to the query subject official website, the class hours of mathematics published by Beijing Normal University are strictly synchronized with the teaching materials. Each class hour has three columns: class essence, class essence and class essence, which are carefully selected by outstanding front-line teachers in China. The questions are rigorous, scientific and rich in content. Classroom refining of mathematics published by Beijing Normal University Press is a set of supplementary books for teaching in various disciplines.