Accountant Wu bought 13 USB flash drives at a computer store on Zhongshan Road, each at 34.5 yuan. He paid the salesperson 500 yuan. How much should he get back?
吴会计到中山路电脑专卖店买了13个U盘，每个U盘34.5元，他付给营业员500元，应找回多少钱？
<gadget id="calculator">34.5 * 13</gadget>
<output>448.5</output>

<gadget id="calculator">500 - 448.5</gadget>
<output>51.5</output>

<result>51.5</result>