Qianqian took 20 yuan to the bookstore to buy books, "Mathematics Exploration" was 6.00 yuan each, and "Chinese Exploration" was 6.5 yuan each. How much money would Qianqian have left after buying these two books?
芊芊拿20元钱到书店买书，《数学探究》每本6.00元，《语文探究》每本6.5元，芊芊买这两本书后还剩多少钱？
<gadget id="calculator">6 + 6.5</gadget>
<output>12.5</output>

<gadget id="calculator">20 - 12.5</gadget>
<output>7.5</output>

<result>7.5</result>