A batch of goods has 40 tons, 20% is transported away for the first time, and 25% is transported away for the second time, how much of this pile of goods is left.
一批货物有40吨，第一次运走20%，第二次运走25%，还剩这堆货的多少．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/5) - (1/4)</gadget>
<output>11/20 = around 0.55</output>

<result>11/20 = around 0.55</result>