Rather than adding up the other digits and calculating the valid checksum value for comparison, it's included in the total to save some programming steps.
In other words, if you had an eight-digit ABA number and wanted to find the correct checksum digit, you'd add those numbers as before.
Many institutions also readily provide it on their web site, if you want to find others.
This number is usually required when setting up a bank account for direct deposits, automated payments, etc.Or when making payments by "paperless" check over the phone or online.These routing numbers include a checksum digit which can be used to help verify if a given number is valid or not. You can usually find your own bank's routing number printed on your checks (look for a nine-digit number at the bottom center of the check).So, having a text field contain that error message might be a good idea.There are other ways to highlight the field in question besides changing the text color, the border color or the fill color could be changed instead, or in addition, just make sure that you are not making the form impossible to read.