The radius of a car wheel is 0.3 meters. If it rolls forward 10 times, how many meters will it move forward?
汽车车轮的半径为0.3米，它向前滚动10圈，前进多少米．
<gadget id="calculator">2 * 3.14 * 0.3</gadget>
<output>1.884</output>

<gadget id="calculator">1.884 * 10</gadget>
<output>18.84</output>

<result>18.84</result>