A product is sold at a 20% discount during the festival, which is 84 yuan cheaper than the original price. How much is the original price of this product?
一件商品在节日期间打八折出售，这样就比原来便宜了84元，这件商品原价多少元？
<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">84 / (1/5)</gadget>
<output>420</output>

<result>420</result>