Could some one provide a step-by-step instruction on:

(1) Create a public function, such as

Public Function Addition(double A, double B) As Double
Addition=A+B
End Function

Public Function Subtraction(double A, double B) As Double
Subtraction=A-B
End Function


(2) compile it to a Addition.dll or to a *.dll file which contains both
Addition and Subtraction?

so that (3) in an Excel worksheet, we just use
=Addition(C1, C2)
To carry on a calculation?

Thanks!