When the temperature of an object is 300 degrees, its volume increases (1/20) compared to its volume at zero degrees. When the temperature is 300 degrees and returns to zero degrees, its volume decreases by how much.
某物体温度在300度时的体积比零度时的体积增加了(1/20)，当温度处300度回到零度时体积减少了多少．
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 + (1/20)</gadget>
<output>21/20 = around 1.05</output>

<gadget id="calculator">(1/20) / (21/20)</gadget>
<output>1/21 = around 0.047619</output>

<result>1/21 = around 0.047619</result>