Learn the logic behind making Boolean choices.
Refresh your skills on the basics of the .NET base classes.
The .NET DateTime class is not just for getting the current date. It can help you do date calculations and much more.
Learn a few helpful statistical functions.
Discover the concept of operator overloading in C# and its application in mathematical libraries.
Basic math operators—such as plus, minus, and modulus—can get you only so far. It is only a matter of time before you find that you need more robust math routines.