The swimming pool in the Olympic venue is about 50 meters long and 20 meters wide, so how many meters is its circumference?
奥运场馆的游泳池长约50米，宽约20米，那么它的周长约为多少米．
<gadget id="calculator">50 + 20</gadget>
<output>70</output>

<gadget id="calculator">70 * 2</gadget>
<output>140</output>

<result>140</result>