# Luhn's algorithm

How do we get the sum = 47?? which digit we have to sum to get this result

1 answers ( 0 marked as helpful)

Hey Shady,

Thanks for reaching out!

When you double every other digit in the sequence, you obtain the set of numbers (14, 8, 18, 6, 6, 16, 6). It is the sum of the digits of these numbers that give you 47:

1+4 (from the number 14)

+8

+1+8 (from the number 18)

+6

+6

+1+6 (from the number 16)

+6

= 47

Hope this helps.

Kind regards,

365 Hristina