Use a square iron sheet with a side length of 1 meter, cut off four of the same largest round iron sheets, and find the utilization rate of this iron sheet.
用一张边长1米的正方形铁皮，剪去四个同样的最大的圆铁皮，求这张铁皮的利用率．
<gadget id="calculator">1 / 2 / 2</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 * (1/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) ** 2</gadget>
<output>1/16 = around 0.0625</output>

<gadget id="calculator">4 / 1</gadget>
<output>4</output>

<gadget id="calculator">3.14 * (1/16) * 4 * 1</gadget>
<output>0.785</output>

<result>0.785</result>