Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles Button1.Click
        Dim Zahl As Double
        Zahl = 3
        If Zahl <> Math.Round(Zahl) Then
            MsgBox("Ungrade!")
        Else
            MsgBox("Grade!")
        End If
    End Sub