What is the perimeter of a rectangle whose length is 13 cm and width is 9 cm?
一个长方形，长是13厘米，宽是9厘米，它的周长是多少厘米
<gadget id="calculator">13 + 9</gadget>
<output>22</output>

<gadget id="calculator">22 * 2</gadget>
<output>44</output>

<result>44</result>