From a square with an area of 40 square centimeters, subtract the largest circle, what is the remaining area in square centimeters? ﹙take 3.14 for π﹚
在一个面积为40平方厘米的正方形中，减去一个最大的圆，剩下的面积是多少平方厘米．﹙π取3.14﹚
<gadget id="calculator">40 / 4</gadget>
<output>10</output>

<gadget id="calculator">3.14 * 10</gadget>
<output>31.4</output>

<gadget id="calculator">40 - 31.4</gadget>
<output>8.6</output>

<result>8.6</result>