Because algebraic evaluation is a compulsory knowledge point in the senior high school entrance examination, it involves a wide range of knowledge and can be combined with practical problems (such as riding a horse, shopping, saving, taxation, etc. ), and the special exploration of algebra problems provides a broad space for the proposers of the senior high school entrance examination, which is a hot spot in recent years. Usually, this kind of problem starts from a list of numbers, an array of numbers, an equation and a set of graphs, and observes and summarizes the law.