'Verify the first two digitd of zip code
    Dim ZipFirstTwo As Integer
    If Not IsNull([State]) And Not IsNull([Zip]) Then
        ZipFirstTwo = Val(Left([Zip], 2))
        Select Case [State]
            Case "MI"
                If ZipFirstTwo < 48 Or ZipFirstTwo > 49 Then
                DoCmd.CancelEvent
                MsgBox "Michigan zip codes must start 48 or 49"
                Me.Undo
                [Zip].SetFocus
            End If
        End Select
    End If