303 is the simplest one in the postgraduate mathematics, because it is aimed at students of economics and management, and the mathematics requirements are not so high after all.

Mathematical analysis is undoubtedly the most difficult, and it is a professional basic course for mathematics majors.

Let's put it this way: Math 1 for postgraduate entrance examination is basically the most difficult to count one, two and three, but the textbook used by students who have taken math 1 is only a simplified version of mathematical analysis, excluding the rigorous proof process of many theorems. So, you should have an idea.

As a math major, you should know a lot about it.