A rectangular vegetable field is 18 meters long and twice as long as it is wide. What is the perimeter of this vegetable field in meters?
一块长方形菜地，长18米，长是宽的2倍，这块菜地的周长是多少米？
<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">18 + 9</gadget>
<output>27</output>

<gadget id="calculator">27 * 2</gadget>
<output>54</output>

<result>54</result>