Private Sub CommandButton1_Click()
If Trim(TextBox4) <> "" Then
If CDbl(TextBox4) > 0 Then
TextBox2 = TextBox2 & IIf(Len(Trim(TextBox2)) = 0, "", "+") & TextBox4
TextBox3 = Evaluate(Replace(TextBox2, Application.DecimalSeparator, "."))
End If
End If
TextBox4 = ""
End Sub