The closest exercise is nothing more than the real questions of the postgraduate entrance examination (assuming that you take the number one, then you can take the real questions of the numbers two and three as exercises). It is highly recommended to use the book "Classification and Analysis of Historical Zhenti" written by Wu Zhongxiang. The biggest advantage of each chapter is that the first part is the first real problem in mathematics over the years (I just take numbers as an example), and the second part is the self-test exercise. All the exercises in this part come from the second and third questions.