The original price of a schoolbag is 40 yuan, how much is the price after the 20% discount?
一个书包的原价40元，八折后的价钱是多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">40 * (4/5)</gadget>
<output>32</output>

<result>32</result>