To celebrate Children's Day, Xinhua Bookstore is offering 5 sets of children's encyclopedias for free at 54 yuan each. Buy 5 sets at a time, how much is each set cheaper?
新华书店为庆祝六一儿童节，买5套儿童百科全书送一套，每套54元．一次买5套，每套便宜多少钱？
<gadget id="calculator">5 + 1</gadget>
<output>6</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">54 * (5/6)</gadget>
<output>45</output>

<gadget id="calculator">54 - 45</gadget>
<output>9</output>

<result>9</result>