Unit 2 - E2 Error detection - Check Digit
Check digit - correct answer A form of error detection. A check digit is the final
digit in a code of numbers. It is calculated from all the other digits in the code. Its purpose is to spot
human errors on data entry.
Where is the check digit located? - correct answer The last one or two digits at
the end of the account number or ISBN number.
What is an example of a check digit standard? - correct answer ISBN 13
How does a check digit detect errors? - correct answer 1- The sender runs an
algorithm to generate the check digit and adds it to the end of the number. 2- The recipient runs the
same algorithm across the number.
3- Recipient then compares the generated check digit against the one sent and if they don't match the
recipient knows there is an error in the code.
What is the advantage of using a check digit? - correct answer You can detect
simple errors in the input of a series of digits such as a single mistyped digit.
What is the disadvantage of using a check digit? - correct answer You will be
able to detect that an error has occurred but you will not be able to detect the erroneous digits.
Give an example of when check digits used. - correct answer They are used as
a form of validation when a customer enters their credit card number.
Identify the check digit in this ISBN number:
ISBN 1 84146 201 2 - correct answer 2
Identify the check digit in this credit card number:
