The school has a circular open space with a diameter of 40M. It is planned to build a circular flower bed in the center, and pave a cement pavement with a width of 6 meters in the rest. How many square meters is the cement pavement?
学校有一块直径是40M的圆形空地，计划在正中央修一个圆形花坛，剩下部分铺一条宽6米的水泥路面，水泥路面的面积是多少平方米？
<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">20 - 6</gadget>
<output>14</output>

<gadget id="calculator">14 ** 2</gadget>
<output>196</output>

<gadget id="calculator">400 - 196</gadget>
<output>204</output>

<gadget id="calculator">3.14 * 204</gadget>
<output>640.56</output>

<result>640.56</result>