If you don't aim at exams, but just want to improve your math knowledge so that you can cope with it at work, or even deepen it, then you must remember your original intention. Therefore, the following suggestions are put forward:

1. Just be familiar with the basic concept theorem.

2. You can do a few basic questions to consolidate, but don't do difficult questions, because it is unnecessary (you don't want to take the college entrance examination) and it is time-consuming and laborious.

3. Only learn the mathematics knowledge closely related to the work, that is, what is needed in the work. For example, plane geometry in junior high school and solid geometry in senior high school, which will not be used in your homework, can be completely omitted.

University must study calculus.

One of your current studies is to supplement the foundation (otherwise you can't understand calculus in college), and the other is to pay attention to the breadth of knowledge, but you don't need to go deep into every knowledge point, which is contrary to the study in high school, but it is the correct learning method after work.

6. Because you want to work better in the end, according to your description, I suggest you study the statistics textbook again. Also pay attention to the width and understand the basic concepts and formulas. You can look through books at any time when you actually need them. Of course. You check it more often, and you will remember it if you use it more.