The sum of the length and width of a rectangular vegetable field is 8 meters. What is the perimeter of the rectangular vegetable field in meters?
一个长方形的菜地，长与宽的和是8米，这个长方形菜地的周长是多少米．
<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<result>16</result>