The radius of the outer circle of a circle is 10cm, and the radius of the inner circle is 8cm. What is the area of the circle in cm**2?
一个环形的外圆半径是10cm，内圆半径是8cm，这个环形的面积是多少cm**2？
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">8 ** 2</gadget>
<output>64</output>

<gadget id="calculator">3.14 * 64</gadget>
<output>200.96</output>

<gadget id="calculator">314 - 200.96</gadget>
<output>113.04</output>

<result>113.04</result>