A rectangular vegetable field is 7 meters long, and its width is 3 meters shorter than its length. How long is the fence around it?
一块长方形的菜地，长7米，宽比长短3米，四周围上篱笆长多少米？
<gadget id="calculator">7 - 3</gadget>
<output>4</output>

<gadget id="calculator">7 + 4</gadget>
<output>11</output>

<gadget id="calculator">11 * 2</gadget>
<output>22</output>

<result>22</result>