Give us an example of what you mean, ie do you want numbering to be 1A, 2B, 3C or what?
If you set up an autonumber field "No_A" and another text field "TextB" which will be your primary key; run a line of code so that when a new record is created on a form it runs:
Me!.textB = Me!.No_B & "A" (note you will need to name text boxes on your form more appropriatly!)
This will take your autonumber field and add A onto the end of each one.
Hope this helps....
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