I am trying to extrapolate what the checksum would be where the exact same change happens in a text string.
The final two digits reduce by 18 places. Where the last two digits are 19-99 this is really easy to calculate
My issue is when the existing two digits are less than 18
I know in all scenarios the last two digits reduce by 18 places.
Known working examples:
Checksum 33 becomes 15
Checksum 61 becomes 43
Checksum 65 becomes 48
Checksum for 12 becomes 5B
Checksum for 02 becomes 4B
I need to work out what the new checksum would be for 2C and 1E and a wee explanation of how I can then work out any similar sum
I have outlined the examples above