The lane of the swimming pool is 50 meters long, Xiao Ming swam 4 times, how many meters did Xiao Ming swim in total?
游泳池的泳道长50米，小明游了4个来回，小明一共游了多少米？
<gadget id="calculator">50 * 2 * 4</gadget>
<output>400</output>

<result>400</result>