Final answer:
A check digit is a control that can be used to reduce errors when entering an account number into a computer.
Step-by-step explanation:
The control that can be used to reduce the likelihood of an error occurring when an account number is entered into a computer is a check digit. A check digit is a mathematical algorithm applied to the digits of an account number to generate a final digit. This final digit acts as a form of error detection and can be used to validate the accuracy of the entered account number.
An example of a check digit is the Luhn algorithm, commonly used in credit card numbers. The algorithm uses a series of calculations to generate a digit that is appended to the end of the credit card number. When the credit card number is entered into a system, the system can check the validity of the number by verifying that the calculated check digit matches the one appended to the entered number.
By using a check digit, the likelihood of errors being entered into the computer system is reduced. Even if a digit is mistyped or a number is entered incorrectly, the system can identify the error and prompt the user to re-enter the correct number.