A shopping mall held a "Welcome to May Day" promotional activity. Buy five badminton rackets and get one free. A badminton racket costs 8.5 yuan per pair, and the school bought 12 pairs. How much did it cost?
某商场举办"迎五一"促销活动，所有的羽毛球拍买五副送一副．一种羽毛球拍每副8.5元，学校买了12副，花了多少钱？
<gadget id="calculator">5 + 1</gadget>
<output>6</output>

<gadget id="calculator">12 / 6</gadget>
<output>2</output>

<gadget id="calculator">2 * 5</gadget>
<output>10</output>

<gadget id="calculator">8.5 * 10</gadget>
<output>85</output>

<result>85</result>