The difference between the two piles of goods is 20 tons. After they have been transported 20%, how many tons is the difference between the two piles of goods?
两堆货物相差20吨，它们各运走20%后，这时两堆货物相差多少吨．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">100 * (4/5)</gadget>
<output>80</output>

<gadget id="calculator">100 * (4/5) * (4/5)</gadget>
<output>64</output>

<gadget id="calculator">80 - 64</gadget>
<output>16</output>

<result>16</result>