The original price of a commodity is 120 yuan, and now it is sold at a 20% discount. How much is it cheaper?
一种商品的原价是120元，现打八折销售，便宜了多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">120 * (4/5)</gadget>
<output>96</output>

<gadget id="calculator">120 - 96</gadget>
<output>24</output>

<result>24</result>