Hello FFFCU, and welcome,
Without a bigger extract from the report, in CODE tags, it's hard to see the full picture, so this may not be the simplest answer...
You can do this using Calculated Fields in the table view. I'm assuming that you don't need to add up account numbers so I've left everything here as character strings.
If you need help trapping, please do post a sample showing the complete line, and indicate if the report is fixed width or PDF...