A schoolbag is 48.8 yuan after 20% discount, how much cheaper than the original price.
一个书包打完8折后是48.8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">48.8 / (4/5)</gadget>
<output>61</output>

<gadget id="calculator">61 - 48.8</gadget>
<output>12.2</output>

<result>12.2</result>