A piece of rectangular paper with a length of 10 decimeters and a width of 8 decimeters, after cutting out the largest circle, what is the remaining area?
一张长10分米、宽8分米的长方形纸片，剪下一个最大的圆后，剩下的面积是多少．
<gadget id="calculator">10 * 8</gadget>
<output>80</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

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

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

<gadget id="calculator">80 - 50.24</gadget>
<output>29.76</output>

<result>29.76</result>