A rectangular lawn is 20 meters long and 12 meters wide. There is a circular flower bed in the middle with a radius of 4 meters. What is the area of the lawn?
一个长方形草坪，长20米，宽12米，中间有一个圆形花坛，半径是4米，求草坪的面积是多少？
<gadget id="calculator">20 * 12</gadget>
<output>240</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">3.14 * 16</gadget>
<output>50.24</output>

<gadget id="calculator">240 - 50.24</gadget>
<output>189.76</output>

<result>189.76</result>