A product is sold at 240 yuan after a 20% discount, which is how much cheaper than the original price.
一种商品打八折后售价为240元，比原价便宜多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">240 / (4/5)</gadget>
<output>300</output>

<gadget id="calculator">300 - 240</gadget>
<output>60</output>

<result>60</result>