commodity is sold at a 20% discount. If the original price of this commodity is 50 yuan, what is the current price?
一种商品打八折销售，如果这种商品原价50元，现价是多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">50 * (4/5)</gadget>
<output>40</output>

<result>40</result>