Xiao Ming went to the swimming pool to swim, and swam 3 back and forth. The swimming lane was 100 meters long. How many meters did he swim?
小明去游泳池游泳，游了3个来回，泳道长100米，他游了多少米．
<gadget id="calculator">100 * 2 * 3</gadget>
<output>600</output>

<result>600</result>