The original price of a commodity is 1,200 yuan, and now it is sold at a 20% discount. How much is it cheaper than the original price?
一件商品原价1200元，现在打八折出售，比原价便宜多少元．
<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">1_200 * (1/5)</gadget>
<output>240</output>

<result>240</result>