A piece of iron wire is 20 meters long. After cutting off how many meters, 20% of the total length remains.
一根铁丝长20米，剪去多少米后，还剩全长的20%．
<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">20 * (4/5)</gadget>
<output>16</output>

<result>16</result>