If the diameter of two circles differs by 2 cm, what is the difference in circumference of the two circles?
两圆的直径相差2厘米，两圆的周长相差多少厘米
<gadget id="calculator">3.14 * 3</gadget>
<output>9.42</output>

<gadget id="calculator">3.14 * 1</gadget>
<output>3.14</output>

<gadget id="calculator">9.42 - 3.14</gadget>
<output>6.28</output>

<result>6.28</result>