The original price of a schoolbag is 30 yuan, and now there is a 20% discount. What is the current price?
一个书包原价30元，现在八折优惠，现价是多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">30 * (4/5)</gadget>
<output>24</output>

<result>24</result>