Chengdu junior high school mathematics teaching assistant "point midpoint" is good. Diandian is a famous supplementary teaching material edited by Rong and has become one of the favorite teaching materials for teachers, parents and students. Annual sales hit a record high. Rong is an entrepreneur specializing in the planning, editing, auditing and distribution of supplementary books, mainly serving junior and senior high school students and teachers. Founded in 1995, the company expanded its scale from 1997, devoted itself to the planning and editing of supplementary books and expanded to the front of book publishing.