It may just be me, but I cannot figure out what you are asking for. What does the "Weight" number have to do with what you want? What do you mean "the answer is 4 and looks like this - 019338393"? Where does the 4 come from? What does it have to do with the number 019338393? I think you might get more (better) answers if you explain in more detail what you are trying to do.
Hi, I'm not exactly sure how to explain, but I"m looking to see how to use the below formula in excel. I want to use the check digit 01933839 vs. 139 in the example below.
Luhn algorithm. This algorithm, also known as the "modulus 10" or "mod 10" algorithm, is very common. For example, it's the algorithm used by credit card companies to generate the final digit of a credit card.
Given an identifier, let's say "139", you travel right to left. Every other digit is doubled and the other digits are taken unchanged. All resulting digits are summed and the check digit is the amount necessary to take this sum up to a number divisible by ten.
Got it? All right, lets try the example.
Work right-to-left, using "139" and doubling every other digit.
9 x 2 = 18
3 = 3
1 x 2 = 2
Now sum all of the
digits (note '18' is two digits, '1' and '8'). So the answer is '1 + 8 + 3 + 2 = 14' and the check digit is the amount needed to reach a number divisible by ten. For a sum of '14', the check digit is '6' since '20' is the next number divisible by ten.
