Numerical analysis is an interesting subject. If you are not a math major, I suggest you start from the following aspects:

1. Understand basic mathematical knowledge, such as calculus and linear algebra. This knowledge is the basis of numerical analysis and other advanced mathematics courses.

2. Learn the basic methods and skills of numerical calculation, such as interpolation, numerical integration and numerical differentiation. These methods and techniques are the core content of numerical analysis.

3. Choose a suitable textbook, such as numerical calculation method and numerical analysis. These textbooks are comprehensive and can help you learn numerical analysis systematically.

4. do more exercises, such as some topics on LeetCode. These exercises can help you consolidate what you have learned and improve your programming ability.