Core 5 EF1 | Professor Dexter | Spring 2001

Homework 7:  Codes

For questions requiring a numeric answer, show your work.

  1. What is the check digit for a Postal Service money order which begins with 7234541780?

  2. What is the check digit for the UPC code which begins with 03890000143?

  3. Given the UPC code which begins with 03890000143, the previous question asked you to determine the check digit. Now use the full code (including the check digit) to look up the product in the UPC database. What product does this code represent?

  4. Explain why the airline ticket number scheme will catch the error 751.. typed in as 157..., (i.e. the 1 and the 7 are interchanged) but the UPC scheme will not.

  5. Explain why the UPC scheme will catch the error 751.. typed in as 571..., but the Postal Service money order scheme will not.

  6. Is this a valid ISBN number: 2-705-45214-X? Explain.

  7. Given an ISBN number that begins with the digits 0-394-84494, what is the check digit?

  8. The previous question asked you to find the check digit for the ISBN number which begins with 0-394-84494. Use the full ISBN number, including the check digit, to look up the book through amazon.com. (Note that you must not type in the dashes.) Who is the author of the book?

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