The length of a rectangular field is 60 meters and the width is 40 meters. How many meters is it to run around it twice?
一个长方形球场的长是60米，宽是40米，绕它跑两圈是多少米．
<gadget id="calculator">60 + 40</gadget>
<output>100</output>

<gadget id="calculator">100 * 2 * 2</gadget>
<output>400</output>

<result>400</result>