A rectangle is 10 meters long and 8 meters wide, what is its perimeter?
一个长方形长是10米，宽是8米，它的周长是多少分米．
<gadget id="calculator">10 + 8</gadget>
<output>18</output>

<gadget id="calculator">18 * 2 * 10</gadget>
<output>360</output>

<result>360</result>