How much is a 18 yuan children's playground marked with a 20% discount.
一张18元钱的儿童乐园标打八折后是多少元．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">18 * (4/5)</gadget>
<output>72/5 = around 14.4</output>

<result>72/5 = around 14.4</result>