A stationery store buys a ballpoint pen and a fountain pen, each ballpoint pen is 1.5 yuan, each pen is 3 yuan more than each ballpoint pen, Xiaohong gives the salesperson 10 yuan, how much should I get back?
文化用品商店买一枝圆珠笔和一枝钢笔，每枝圆珠笔1.5元，每枝钢笔比每枝圆珠笔多3元，小红给售货员10元钱，应找回多少元？
<gadget id="calculator">3 + 1.5 + 3</gadget>
<output>7.5</output>

<gadget id="calculator">10 - 7.5</gadget>
<output>2.5</output>

<result>2.5</result>