Operators are basically symbols, either single characters or a specific combination of several characters, which specify operations (math, obviously, but also indexing, function calls and so on) to perform in an expression. If you have read the previous articles in this tutorial, you have already seen several operators, like the assignment operator (a single equal sign) used when you learned about variables and so on.
So far, we haven't really talked about these operators, because they have been mostly self-explanatory. However, that is not the case for all operators in C# (and believe me, there are a lot), and even for those who makes sense when seeing it, it's nice to get a proper name for it and perhaps even learn a bit more about how it works internally.
In the next several articles, we'll do just that: we will look into many of the C# operators, both the simple and the not-so-simple, talk about what they do and show you how you can use them. You will find some very valuable information in these articles, which will give you a better understanding of what goes on when your code is interpreted, but it will also be a bit more theoretical than what you have previously read. If it turns out to be too much for you right now, then feel free to skip some of it and return later.