How to show the Record Number on a Sub-Form just like Running Sum In a Report?

Define 'Record Number' ....
There is no Record Number per se in an Access Table.  The closest thing is the *relative* record number you see in a Datasheet View form (sub form) when you have the Navigation Buttons enabled. But even that record number is subject to change as records are added/deleted, etc.
I supposed you could ... invent some scheme but not sure it's work it ....

Hello Joe:

If I say 'raw number' in  the sub-form, is it OK?
What do you call the "record selectors" in the property sheet of the sub-form?
My sub-form is based on a query.

Pls guide me to the right Access terminology as am new to this.

Thanks

Tables in relational databases do not have record numbers.  That is an old dBase concept.  Spreadsheets also display record numbers.  But since a table is by definition an unordered set, a record number doesn't make any sense.

What are you trying to do with the record number?  Will it be permanent so that record 1 will always be record 1 regardless of how the subform is currently sorted?

Hello Pat,,,

Once I pick the record Number, It will used just as a label for some documents in a separate file.
So there is NO infringing to the  DB relationships, etc.
If the record is not there after leaving the form, nothing will happen.
You can trust me on these concerns (after 40 years in the IT . . .  lol, old enough).  
This is a forced Requirement by the Company Standards and Audit rules.
No one cares about unique Primary Keys and so on or extra one field here or there.
A reference to a Cheque   or  Promissory Note has to be constructed in accordance with a certain scheme and that is it.
Users and management do not care about these technicalities.

Thanks.

Dear Pat / Gustav,,,

I think now we are synchronized on the same wave.
I will be trying it soon and let you know.

Thanks a lot.

Dear Pat / Gustav,,,

Wonderful . . . and . . . .  Working  beautifully.

I change the sorting to be on the Foreign Key (FK), a Date,  and the new  Row No.

The sorting on the Row No. will be for the sequence of presenting the rows in the sub form.    Is this OK?

Many many Thanks.

Well, you should not sort on the calculated row number ... makes little sense.

/gustav

The sorting on the Row No. will be for the sequence of presenting the rows in the sub form.    Is this OK?

Yes, that is correct assuming you are using my suggestion of creating the number when the record is created so that it is permanent.  It is not clear to me what you are actually doing since Gus and I gave you completely different solutions.  Gus' solution gives you an on the fly number that could change every time you open the form.  I gave you a permanent solution that stays with the record similar to a check number.

Dear PAT,,,

Is there any tool within the Win 10 by which I grab some rectangular area from the screen so I can pass it to you here?
In the old days, I used to use ZapGrab 3rd party. Anything similar.
Thanks.

There is the native Snipping Tool

/gustav

You might have to use Cortina to find the Snipping Tool if it isn't in your tray.  Alternatively you can use the Print Screen and then use Paint to trim it down.  You might also have to search for Paint if you can't find it under accessories.

Snagit ... best ever ... cool in SO many ways

https://www.techsmith.com/screen-capture.html

Snagit is excellent and I use it at home but it isn't free.  It isn't expensive as far as useful tools go be it still might matter.  For documentation, I always use Snagit because it has the ability to grab dropped combos or menus and the free tools lack that capability.  For day-to-day stuff at a client site, I use the Snipping Tool built into Windows.

Thanks a Lot Gustav & Pat.

It was very helpful and professional.

You are welcome!

/gustav