Hello, Yang Chao graduated from Tsinghua University with a bachelor's degree in postgraduate mathematics. Yang Chao, a famous mathematics teacher in the postgraduate entrance examination, has a Ph.D. in economics, a postdoctoral fellow at California State University, and a visiting scholar at Stanford University. He has been teaching postgraduate entrance examination mathematics for many years. He combines philosophical logic with mathematical logic, develops exclusive problem-solving ideas, original oral arithmetic formulas, and proposes the review concept of repeatedly training the "three major calculations" in the basic stage. From 2012 to 2015, he was the first batch of New Oriental Online postgraduate entrance examination mathematics students. Teacher; In 2016, he joined Yantu Postgraduate Entrance Examination and served as the chief lecturer of postgraduate entrance examination mathematics; In 2018, he was a postdoctoral fellow at California State University, Monterey Bay; In May 2019, as a visiting scholar at Stanford University, he went to Stanford University for an academic exchange visit; November 2019 In August, he participated in the National Advanced Training for Higher Mathematics Teachers held at Fudan University and delivered a speech. The theme of the speech was "How to teach advanced mathematics courses that interest students." The editor-in-chief "24 Lessons in Mathematics for the Postgraduate Entrance Examination", "A Comprehensive Guide to the Difficulties of Mathematics for the Postgraduate Entrance Examination" and "139 High Score Series - Must-Do Exercise Bank for the Postgraduate Entrance Examination Mathematics". This collection of handwritten exercises summarizes the source of the questions, subdivides the types of questions, and differentiates the difficulty. It includes 3 original questions from the 20-year postgraduate entrance examination. "100 Must-Do Questions Before the Exam" is a book of pre-test questions for mathematics, which covers the original questions and similar questions many times. "Super Detailed Explanation of Postgraduate Entrance Examination Mathematics" strictly follows the requirements of the examination syllabus, conducts a comprehensive analysis of the knowledge points of Postgraduate Entrance Examination Mathematics, and highlights the points that are easy to confuse and make mistakes. The book "986 Must-Do Questions in Mathematics for Postgraduate Entrance Examination" is divided into three parts: advanced mathematics, linear algebra, probability theory and mathematical statistics. The content of each chapter is divided into basic questions and intensive questions.