By Dan Mabbutt
As I said, this isan advanced topic, so we'll see more about it later in the course but here's an experiment you can do now to see the difference.
Adding System.Math to the Sqrt object is called qualifying it and if you have to use Sqrt very much in your code, you will get very tired of typing the qualification over and over. So VB.NET gives you a way to let the computer do the work for you and this is the Imports statement.
This leads directly to my second point. This is a powerful and fundamental concept and it's at the very heart of Object Oriented Programming (OOP). It's especially important when you start using "third party software" for your libraries of objects rather than just Microsoft libraries. (Maybe this is another example of MS Press tunnel vision?) For example, if you want to use what are called "complex numbers" (an advanced mathematical rather than programming topic which we won'tcover later) you will find that there's really nothing in .NET to help out. Fortunately, there ARE libraries available from third party software companies that DO let you use complex numbers. (For example, see this page.)