A rectangle is 8 cm long and 3 cm wide, what is the perimeter of the rectangle in cm?
一个长方形长是8cm，宽是3cm，这个长方形的周长是多少cm．
<gadget id="calculator">8 + 3</gadget>
<output>11</output>

<gadget id="calculator">11 * 2</gadget>
<output>22</output>

<result>22</result>