The area of a square colored paper is 80cm**2. If a largest circle is cut out, what is the area of the remaining part?
一张正方形彩纸面积是80cm**2．从中挖去一个最大的圆，剩下部分的面积是多少平方厘来？
<gadget id="calculator">80 / 4</gadget>
<output>20</output>

<gadget id="calculator">3.14 * 20</gadget>
<output>62.8</output>

<gadget id="calculator">80 - 62.8</gadget>
<output>17.2</output>

<result>17.2</result>