A square log with a side length of 20 cm and a length of 2 meters, how much wood needs to be sawn to be the largest log?
一个横断面边长是20厘米，长2米的方木，要锯成是最大圆木，需要锯下多少木料？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 * (1/5) * (1/5)</gadget>
<output>2/25 = around 0.08</output>

<gadget id="calculator">(1/5) / 2</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) ** 2</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">3.14 * (1/100) * 2</gadget>
<output>0.0628</output>

<gadget id="calculator">(2/25) - 0.0628</gadget>
<output>0.0172</output>

<result>0.0172</result>