Dan works at a very busy ice cream parlor during the main rush hours. For random customers paying in cash, Dan quotes a price higher than the one...

Dan works at a very busy ice cream parlor during the main rush hours. For random customers paying in cash, Dan quotes a price higher than the one provided by the cash register. Dan then pockets the difference between the actual price and the price quoted to the customer and rushes off to the next customer. What kind of fraud is being committed, and how can this fraud be prevented by the employer