A rectangular piece of paper, 60 cm long and 40 cm wide. Cut out a circle as large as possible from this piece of paper. What is the remaining area in square centimeters?
一张长方形纸片，长60厘米，宽40厘米．用这张纸剪下一个尽可能大的圆．剩下的面积是多少平方厘米？
<gadget id="calculator">60 * 40</gadget>
<output>2_400</output>

<gadget id="calculator">40 / 2</gadget>
<output>20</output>

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

<gadget id="calculator">3.14 * 400</gadget>
<output>1_256</output>

<gadget id="calculator">2_400 - 1_256</gadget>
<output>1_144</output>

<result>1_144</result>