A rectangular vegetable field with a length of 14 meters and a width of 6 meters is to be fenced around the vegetable field. How long is the fence?
一块长14米，宽6米的长方形菜地，要在这块菜地的四周围上篱笆，篱笆长多少米？
<gadget id="calculator">14 + 6</gadget>
<output>20</output>

<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<result>40</result>