A jacket is 80 yuan cheaper than the original price after a 20% discount. What is the original price of this jacket?
一件上衣，打八折后比原价便宜80元，这件上衣原价是多少元．
<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">80 / (1/5)</gadget>
<output>400</output>

<result>400</result>