A playground is 150 meters long and 90 meters wide, what is its perimeter in meters?
一个操场长150米，宽90米，它的周长是多少米？
<gadget id="calculator">150 + 90</gadget>
<output>240</output>

<gadget id="calculator">240 * 2</gadget>
<output>480</output>

<result>480</result>