Each character in the scanned data is assigned a numeric value (see OCR Check Digit Multiplier). Each digit representing a character in the scanned data is multiplied by its corresponding digit in the multiplier, and the sum of these products is computed. The check digit passes if this sum modulo Check Digit Modulus is zero.
For example:
Scanned data numeric value is
132456
(check digit is 6)
Check digit multiplier string is
123456
Digit
1
3
2
4
5
6
Multiplier
1
2
3
4
5
6
Product
1
6
6
16
25
36
Product add
1+
6+
6+
16+
25+
36=
90
The Check Digit Modulus is 10. It passes because 90 is divisible by 10 (the remainder is zero).
