Tickets for the amusement park used to be 30 yuan a piece, and there was a 20% discount during the "June • 1st" period. How much can I save by buying a ticket?
游乐场的门票原来30元一张，"六•一"期间八折优惠，购买一张门票能省多少元？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">30 * (1/5)</gadget>
<output>6</output>

<result>6</result>