There is a piece of clothing in the supermarket whose original price is 200 yuan. Now it is sold at 20% off. How much is it cheaper than before?
超市里有一件衣服原价200元，现在八折出售，比原来便宜了多少元？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">200 * (1/5)</gadget>
<output>40</output>

<result>40</result>