Pei Liwen doesn't need to brush math. According to the relevant public information inquired, there is no need to brush Pei's mathematics. These two books are too big and thick to waste time, especially Pei's book, which is as thick as 1000 pages. There is no need to brush so many questions in mathematical analysis. Those things are old-fashioned, and they will never be used again. Instead of brushing so many mathematical analysis exercises, it is better to spend time on functional analysis of real variable functions.