There is a ring, the circumference of the inner circle is 31.4 cm, and the circumference of the outer circle is 62.8 cm, what is the width of the ring in cm?
有一个圆环，内圆的周长是31.4厘米，外圆的周长是62.8厘米，圆环的宽是多少厘米？
<gadget id="calculator">62.8 / 3.14 / 2</gadget>
<output>10</output>

<gadget id="calculator">31.4 / 3.14 / 2</gadget>
<output>5</output>

<gadget id="calculator">10 - 5</gadget>
<output>5</output>

<result>5</result>