In order to green the campus, the school planted a rectangular lawn in the center, which is 18 meters wide and 6 meters shorter than the length. What is the perimeter of this rectangular lawn in meters?
为了绿化校园，学校在中心位置种植了一块长方形草坪，宽是18米，比长短6米，这块长方形草坪的周长是多少米？
<gadget id="calculator">18 + 6 + 18</gadget>
<output>42</output>

<gadget id="calculator">42 * 2</gadget>
<output>84</output>

<result>84</result>