A rectangular lawn is 10 meters long and 8 meters wide. What is the perimeter of the lawn?
一块长方形草坪的长为10米，宽为8米，这块草坪的周长是多少米？
<gadget id="calculator">10 + 8</gadget>
<output>18</output>

<gadget id="calculator">18 * 2</gadget>
<output>36</output>

<result>36</result>