Taken from C# 205 Lesson 8 Using Classes Part 2:MathSolver
 
 I created a custom class and use it in the form
 
 Private Sub btnGO_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGO.Click

        '---define and initialize
        Dim firstNumber As Integer = 0
        Dim secondNumber As Integer = 0
        Dim myResult As Integer = 0

        firstNumber = CInt(txtFirst.Text)
        secondNumber = CInt(txtSecond.Text)

        Dim getAnswer As New DoMath           'create object from our new class
        myResult = getAnswer.Compute(firstNumber, secondNumber, myOperand)   'pass numbers and compute

        txtAnswer.Text = myResult.ToString    'convert to string and display

    End Sub
    
    
    Created 8/8/06 for C# 2005
'This class has one method that computes the answer sent to it. The method accepts 3 parameters:
'the first number, second number, the operation (+,-,*,/) and returns an integer as the answer.


Public Class DoMath
    ''' <summary>
    ''' This method accepts two integers and the operand (+,-,*,/) and returns the answer as an integer.
    ''' </summary>
   
    Public Function Compute(ByVal x As Integer, ByVal y As Integer, ByVal z As String) As Integer

        Dim theResult As Integer

        Select Case z
            Case "+"
                theResult = x + y

            Case "-"
                theResult = x - y
            Case "*"
                theResult = x * y

            Case "/"
                theResult = x / y
        End Select


        Return theResult

    End Function
End Class