A rectangular flower bed is 5 meters long and 3 meters wide. What is the perimeter of this rectangle?
一个长方形花坛的长是5米，宽是3米．这个长方形的周长是多少？
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<result>16</result>