Given that the area of the outer circle is 5m**2 and the area of the inner circle is 3m**2, what is the area of the ring?
已知外圆的面积为5m**2，内圆的面积为3m**2，圆环的面积是多少．
<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<result>2</result>