A product is priced at 100 yuan after a 20% discount. What is the original price?
一种商品打八折后售价是100元，原价是多少．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">100 / (4/5)</gadget>
<output>125</output>

<result>125</result>