What is the perimeter of a rectangle with a length of 20 decimeters and a width of 6 decimeters
一个长方形的长20分米，宽6分米，它的周长是多少
<gadget id="calculator">20 + 6</gadget>
<output>26</output>

<gadget id="calculator">26 * 2</gadget>
<output>52</output>

<result>52</result>