The radius of the inner circle of a circular runway is 30 meters, and the width of the runway is 2 meters. How many meters does it take to run around the outer circle than to run around the inner circle?
一个环形跑道的内圈半径为30米，跑道宽2米，绕外圈跑一圈比绕内圈跑一圈要多跑多少米．
<gadget id="calculator">30 + 2</gadget>
<output>32</output>

<gadget id="calculator">3.14 * 2 * 32</gadget>
<output>200.96</output>

<gadget id="calculator">3.14 * 2 * 30</gadget>
<output>188.4</output>

<gadget id="calculator">200.96 - 188.4</gadget>
<output>12.56</output>

<result>12.56</result>