What is the perimeter of a rectangle with a length of 5 decimeters and a width of 3 decimeters?
一个长为5分米，宽3分米的长方形，周长是多少分米．
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

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

<result>16</result>