Brush 660 first. According to the difficulty of postgraduate mathematics, it is generally recommended to start with the number of 660 questions. The difficulty and scope of the 660 math questions for postgraduate entrance examination are moderate, which is suitable for use as introductory materials and foundation consolidation. After completing a certain number of 660 questions, if you feel that you can cope with more difficult questions, you can gradually turn to 1800 questions, choose the appropriate time and quantity according to your own situation, and gradually improve your math level.