There is a circular flower bed with a radius of 4m in the middle of a rectangular lawn with a length of 20m and a width of 12m. What is the area of the lawn in square meters?
在一块长20m，宽12m的长方形草坪中间有一个半径为4m的圆形花坛，草坪的面积是多少平方米？
<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>