how to calculate hkid check digit?
['Convert the prefix alphabet to a numeric value. ... ', 'Convert each HKID digit to a number. ... ', 'Calculate remainder of (Step 1 result + Step 2 result)/11. ... ', 'Check Digit = 11 – result of Step 3. ... ', 'The Check Digit should contain only a single digit, otherwise further convert using the below rules.']