If the diameter of a circle increases from 6cm to 10cm, how much does the circumference increase?
一个圆的直径由6cm增加到10cm，周长增加多少？
<gadget id="calculator">2 * 3.14 * 10</gadget>
<output>62.8</output>

<gadget id="calculator">2 * 3.14 * 6</gadget>
<output>37.68</output>

<gadget id="calculator">62.8 - 37.68</gadget>
<output>25.12</output>

<result>25.12</result>