Although the overall difficulty may not be as high as the last few big questions in the postgraduate entrance examination, it is very helpful for most candidates to carefully complete the training of "660 questions", which can help candidates lay a solid foundation and improve the speed and accuracy of problem solving.

"660 Questions" usually refers to "660 Questions in the Great Sprint of Mathematics Postgraduate Entrance Examination", which is a set of problem sets specially designed for reviewing mathematics for postgraduate entrance examination. The author is Li Yongle and others. This problem set is mainly aimed at the candidates of Mathematics (1) and Mathematics (2).