A bottle of air freshener is 30 yuan, buy 5 bottles and get 1 bottle free, Aunt Zhang buys 5 bottles, how much is each bottle cheaper?
一瓶空气清新剂30元，买5瓶送一瓶，张阿姨买5瓶，每瓶便宜多少元？
<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">30 * (5/6)</gadget>
<output>25</output>

<gadget id="calculator">30 - 25</gadget>
<output>5</output>

<result>5</result>