Use System.Type.InvokeMember() / Invoke Method Dynamically Using Reflection?

I understood that we can use System.Type.InvokeMember() to invoke method dynamically using Reflection, but I couldn't get proper example to show how to work on it. Can anyone please explain how to do it in
Visual Studio 2010

Just for practice purpose I have created one class called MathFunctions like below:
namespaceCSHWEB
{
public
class
MathFunctions
{
public
double
SimpleInterest(double
PrinicipalAmount, double
TimePeriod, double RateOfInterest)
{
return
(PrinicipalAmount * TimePeriod * RateOfInterest) / 100.0;
}
}
}

Now,
how can I invoke above method SimpleInterest with its parameters without instantiating the class?