The computer sums the first four digits of a customer number to calculate the value of the fifth digit and then compares that calculation to the number typed during data entry. this is an example of a:

Answer to the following is check digit verification or validation.

Explanation:

The check digit is an important function of the validation or verification.

yes the ansewer is c bc you can look it up!

if you go to ask a question say ask, there should be something that looks like this. a camera lens.