First of all, "the most basic" economic mathematics should include a complete:

Calculus (from the definition of limit to multiple integrals).

Probability theory (discontinuous and continuous probability models, various density functions, probability functions, Bayesian apriori posteriori, etc. )

Mathematical statistics (law of large numbers, central limit theorem, various statistical indicators, derivation and application of expectation and variance, statistical models, etc.). )

Linear algebra (application of determinant, matrix and matrix)

Personally, I feel that the worst textbook and course in China is linear algebra. I didn't know the meaning of matrix at all in class, and later I learned that it corresponds to a multivariate function, so this thing is very important and will be useful when you study econometrics in the future.

These four courses will be completed before the end of your sophomore year, so they are all the most basic courses.

In the next few slightly advanced courses, economics and finance may be slightly different, but on the whole they are similar. Let me give you an example of finance.

Real variable function, functional analysis, stochastic process, game theory, and necessary learning such as C++/Matlab or other programming tools. In addition, for empirical analysis, it is best to master one of R languages such as SPSS and SAS or statistical analysis programs.

In view of this, I didn't learn well ... I won't introduce it in detail, T-T. ...