The original price of a set of books is 75 yuan, and a 15% discount will be implemented during the "June 1st" period. How much is each set of books cheaper?
一套书原价75元，"六一"期间实行八五折优惠，每套书便宜多少元．
<gadget id="calculator">85 / 100</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">75 * (17/20)</gadget>
<output>255/4 = around 63.75</output>

<gadget id="calculator">75 - (255/4)</gadget>
<output>45/4 = around 11.25</output>

<result>45/4 = around 11.25</result>