The diameter of a bicycle tire is 0.4 meters, how many meters can it move in one round.
一辆自行车车轮胎的直径是0.4米，它滚动一周能前进多少米．
<gadget id="calculator">3.14 * 0.4</gadget>
<output>1.256</output>

<result>1.256</result>