Probleme mit prozentrechnung

[mkinzler]

Delphi-Quellcode:

procedure TForm2.btn_executeClick(Sender: TObject);
var
wert : Extended;
widerstand : Extended;
tolerance: Extended;
prozent: Extended;

begin
    if rb_4rings.Checked then 
    begin
        wert := (cb_ring1.ItemIndex+1)*10 + cb_ring2.ItemIndex;
        case cb_ring3.ItemIndex of
          0: widerstand := wert / 100;
          1: widerstand := wert /10;
          2: widerstand := wert;
          3: ...
end;
...