I created a tip to show Row Number in a Query.
It doesn't save to a table, its only for display purposes.

There are several easy solutions, like the one Alex pointed out, and this one, and this one, to display records with concurrent numbers next to them (display only) or to add the next NEW record with the correct number, but if you delete one, the only way that I can think of to automatically renumber those child records would be to use a Recordset. That's a more advanced concept, and it does involve a little VBA programming. I see you're only an Expert user. I could definitely add this to the next class (Developer 22) and cover it for you, if you want. It actually would fit right in with the class material we're covering now nicely.

thanks that would be great.