In a ring, the diameter of the outer circle is 24 cm, and the radius of the inner circle is 8 cm. What is the area of the ring in square decimeters?
圆环中，外圆的直径是24厘米，内圆的半径是8厘米，求圆环的面积是多少平方分米？
<gadget id="calculator">24 / 2</gadget>
<output>12</output>

<gadget id="calculator">12 ** 2</gadget>
<output>144</output>

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

<gadget id="calculator">144 - 64</gadget>
<output>80</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">3.14 * (4/5)</gadget>
<output>2.512</output>

<result>2.512</result>