Each tape is 12 yuan, buy 5 boxes and get 1 free. Mr. Li buys 5 boxes at a time, how much is each box cheaper?
每盒磁带12元，买5盒送1盒，李老师一次买5盒，每盒便宜多少钱？
<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">12 * (5/6)</gadget>
<output>10</output>

<gadget id="calculator">12 - 10</gadget>
<output>2</output>

<result>2</result>