A rectangular vegetable field is 18 meters long and 15 meters wide. One side of the long side is against the wall. Now we need to fence the other three sides. How long is the fence?
一块长方形菜地，长18米，宽15米，长的有一方靠墙，现在要在其他三面围上篱笆，篱笆长多少米？
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<gadget id="calculator">18 + 30</gadget>
<output>48</output>

<result>48</result>