A commodity is sold with a 20% discount. The original price is 120 yuan. How much is it cheaper now?
一种商品八折销售，原价120元，现在便宜了多少元．
<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">120 * (1/5)</gadget>
<output>24</output>

<result>24</result>