The lanes of the swimming pool are 50 meters long. Xiaohua swam 2 back and forth in this swimming pool, how many meters did he swim in total
游泳池的泳道长50米．小华在这个游泳池里游了2个来回，他共游了多少米
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">50 * 4</gadget>
<output>200</output>

<result>200</result>