The length of a swimming pool is 30 meters, and Xiao Ming swam 3 times back and forth. How many meters did he swim?
一个游泳池的长是30米，小明游了3个来回．他游了多少米？
<gadget id="calculator">30 * 2 * 3</gadget>
<output>180</output>

<result>180</result>