HP Data Entry and Forms Management System (VPLUS) Reference Manual (32209-90024)

580 AppendixD
CHECK DIGIT CALCULATION
MODULUS 10
MODULUS 10
Modulus 10 calculations detect single transpositions and incorrect keying of a single digit.
The calculation is performed as follows:
• The units position and every alternate position of the basic number is multiplied by 2.
• The digits resulting from the multiplication are added to those that were not
multiplied.
• The total is subtracted from the next higher number ending with zero. The result is the
check digit.
Example
Assume a basic number 9 6 4 3 8
Unit and every alternate 9 4 8
Multiplied by 2 18 8 16
Digits not multiplied 6 3
Add them together 1+8+6+8+3+1+6 = 33
Next higher number ending in zero 40
Subtract sum of digits -33
Check digit = 7
The base number with check digit 964387