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Discussion on: Credit card number check

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Tanay Gandhi

Very cool! I'm fascinated, why does it work? Is it due to how credit card companies assign card numbers? How would a couple of math operations check the validity of a credit card number?

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Divyajyoti Ukirde Author

It is used to distinguish valid numbers from mistyped or rather wrong numbers. The check digit is appended to the partial number to generate valid number.