Uncle Wang bought a coat in a shopping mall and spent 400 yuan, which is 20% cheaper than the original price. How much is the original price of this coat? How much discount is this coat on sale for?
王大伯在商场买一件大衣，用去400元，比原来价格便宜20%，这件大衣的原价是多少元？这件大衣是打几折销售的？
<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">400 / (4/5)</gadget>
<output>500</output>

<result>500</result>