The selling price of a pen is 75 yuan, how much is the selling price after 20% off?
一支钢笔的售价是75元，打八折后的售价是多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">75 * (4/5)</gadget>
<output>60</output>

<result>60</result>