Xiaodong took part in a swimming competition and swam 2 back and forth on the 25-meter-long swimming lane. Do you know how many meters Xiaodong participated in?
小东参加游泳比赛，在25米长的泳道上游了2个来回，你知道小东参加的是多少米的比赛吗？
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">25 * 4</gadget>
<output>100</output>

<result>100</result>