In the event of welcoming the World Expo, the school built a new rectangular flower bed, 12.5 meters long and 5.8 meters wide. It will be surrounded by a fence. How long is the fence?
在迎世博活动中，学校新建了一个长方形花坛，长12.5米，宽5.8米，要用篱笆围起来，篱笆长多少米？
<gadget id="calculator">12.5 + 5.8</gadget>
<output>18.3</output>

<gadget id="calculator">18.3 * 2</gadget>
<output>36.6</output>

<result>36.6</result>