Operator symbols in programming languages represent the arithmetic, assignment, relational, and logical functionality that types can perform. Arithmetic operators represent basic math functions, while assignment operators perform math and assignment functions together on a given value. Relational and logical operators evaluate conditions between multiple values, such as greater than, less than, and equal to.
C# also offers bitwise and miscellaneous operators, but these won't come into play for you until you're well on your way to creating more complex applications.
At this point, it only makes sense to cover arithmetic and assignment operators, but we'll get to relational and logical functionality when it becomes relevant in the next chapter.