Cao Yongsheng, a senior math teacher in middle school, graduated from Hunan Normal University and has been teaching for 33 years (worked in No.6 Middle School 15 years, served as head teacher for 4 years, served as section chief 10 years, and taught 6 graduating classes, with excellent results in every college entrance examination); Excellent coach of the national high school mathematics competition, guiding students to participate in the national high school mathematics competition 15 times.