Saw the largest circle from a rectangular wooden board with a length of 9 decimeters and a width of 8 decimeters. How many square decimeters is the remaining board?
从一个长9分米、宽8分米的长方形木板上锯下一个最大的圆，剩下的木板是多少平方分米？
<gadget id="calculator">9 * 8</gadget>
<output>72</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">72 - 50.24</gadget>
<output>21.76</output>

<result>21.76</result>