Who can tell me the rules of positive plus negative, negative plus positive, positive minus negative, negative minus positive? It's better to give another example

Who can tell me the rules of positive plus negative, negative plus positive, positive minus negative, negative minus positive? It's better to give another example

I'll give you a formula I think of myself!
This is about addition and subtraction
Positive and negative are negative
Negative, positive, negative
Zheng Zheng de Zheng
Negative is negative
What is the multiplication and division
Positive and negative are negative
Negative, positive, negative
Zheng Zheng de Zheng
Negative is positive
These are arithmetic operations~