There is a copper coin with "circle outside and square inside". The diameter of the copper coin is 16mm, and the side length of the square in the middle is 4mm. What is the area of this copper coin in mm**2.
有一枚"外圆内方"的铜钱，铜钱的直径为16mm，中间的正方形边长为4mm，这枚铜钱的面积是多少mm**2．
<gadget id="calculator">16 / 2</gadget>
<output>8</output>

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

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

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">200.96 - 16</gadget>
<output>184.96</output>

<result>184.96</result>