A rectangle is 5.4 meters long and 4.6 meters wide, what is its perimeter in meters?
一个长方形的长5.4米，宽4.6米，它的周长是多少米．
<gadget id="calculator">5.4 + 4.6</gadget>
<output>10</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<result>20</result>