The length of a rectangular vegetable field is 5 meters and the width is 3 meters. What is the perimeter of the vegetable field?
一个长方形菜地的长是5米，宽是3米，这块菜地的周长是多少米？
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

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

<result>16</result>