The store held a promotional event. Buy 5 pairs of socks and get 1 free. A pair of socks costs 3.50 yuan. Aunt Li bought 12 pairs, how much did she spend?
商店举办促销活动，所有袜子买5双送1双，一双袜子3.50元，李阿姨买了12双，花了多少元．
<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">3.5 * 10</gadget>
<output>35</output>

<result>35</result>