Xiao Ming goes to the bookstore to buy books. After paying the money, the salesperson returns 6.4 yuan. Xiao Ming finds that the salesperson has changed 1.8 yuan more. How much should the salesperson actually give Xiao Ming?
小明去书店买书，付完钱后，营业员找回6.4元，小明发现营业员多找了1.8元，营业员实际应找给小明多少钱？
<gadget id="calculator">6.4 - 1.8</gadget>
<output>4.6</output>

<result>4.6</result>