A 13-digit barcode ends in a check digit. Write a function barcodeCheckDigit(first12) that gets the first 12 digits as text and gives back the last digit as a number. How: add the digits, but multiply every second one (the 2nd, 4th, 6th ...) by 3. The check digit is (10 - total % 10) % 10.
You will practice: check digits, loops, remainder (%)
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CC BY-SA 4.0
Adapted from a CS Unplugged programming challenge by the University of Canterbury Computer Science Education Research Group, licensed CC BY-SA 4.0.
Changes: Rewritten in our own words as a function with tests, hints and steps, in Python and JavaScript, by Open Cosmos. This version is also CC BY-SA 4.0.
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