Skip to content
Copy of Playground Doc - [SHARED]
About
Table Sort Control
One Click Timer
Time in 1/100 second
Button to log time
Click Thru Button
Working Days Remaining
Working Hours
Delete Empty Rows
Multiple Ranked Lists
Three Most Recent Rows
Search with Regex
Search with Clear Search Button
Search with Accuracy Meter
Find Tags in a Post
Language Translations
Split First and Last Names
Mark Row as Opened
Project Tasks for CAD
Random Numbers
In List 1 not in List 2
Custom Units
Reverse a String or Number
Barcodes / Check Digits
Luhn Algorithm
vCard QR Code
Scientific Notation Display
Lookup Column Schema
Price by Date
Time Zones
Pixel Image
More
Share
Explore

Luhn Algorithm (Luhn Check)

Community Post:
Luhn’s Algorithm
⁠
⁠

Wikipedia Info:
https://en.m.wikipedia.org/wiki/Luhn_algorithm
⁠
⁠

Enter the number without the check digit
Number Reversed reverses the digit order using help from
this post
⁠
⁠
Digit List splits the digits into a list
Every 2nd Digit ~x2 multiplies every second digit by 2 and subtracts 9 if it's larger than 9
Every Other Digit takes the opposite digits from the previous list
Check Digit
sums the Every 2nd Digit ~x2 list and the Every Other Digit list
divides that result by 10 and takes the remainder
subtracts the remainder from 10
Luhn Algorithm Check Digit
0
Number
Digit List
Every 2nd Digit ~x2
Every Other Digit
Check Digit
1
7992739871
1789372997
27649
79797
3
There are no rows in this table
⁠

Want to print your doc?
This is not the way.
Try clicking the ⋯ next to your doc name or using a keyboard shortcut (
CtrlP
) instead.