If a rectangle with a length of 25 cm and a width of 20 cm is subtracted from the largest circle, how many square centimeters are left?
一张长25cm，宽20cm的长方形减去一个最大的圆，还剩多少平方厘米？
<gadget id="calculator">25 * 20</gadget>
<output>500</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">500 - 314</gadget>
<output>186</output>

<result>186</result>