i need to implement weighted modulus 11 formula plz help me

Private ableToProgram As Boolean = False

Private Sub Button1_Click(ByVal sender As System.Object, _
                          ByVal e As System.EventArgs) _
                          Handles Button1.Click
    Dim grade As String
    Dim decision As String

    While Not ableToProgram
        decision = InputBox("Do you want to cheat? (Y/N)", _
                            "Learn to Program", "Y")
        If decision.ToUpper = "Y" Then
            grade = PostAssignmentOnForums()
        Else
            grade = DoWorkYourself()
        End If
        MsgBox(String.Format("You got an {0}", grade))
    End While

    MsgBox("Good Choice!")
End Sub

Function PostAssignmentOnForums() As String
    ableToProgram = False
    Return "F"
End Function

Function DoWorkYourself() As String
    ableToProgram = True
    Return "A"
End Function