A rectangular vegetable field has a width of 100 meters and is 50 meters less than its length. If the rectangular vegetable field is surrounded by a fence, how many meters will the fence be?
一块长方形菜地，宽是100米，比长少50米，如果这块长方形菜地四周围篱笆，篱笆要多少米？
<gadget id="calculator">100 + 50 + 100</gadget>
<output>250</output>

<gadget id="calculator">250 * 2</gadget>
<output>500</output>

<result>500</result>