How can I reference a cell in another Numbers document?

Numbers has never supported referring to a cell of another document. You may, of course, post feedback to Apple using the menu item "Numbers Provide Numbers Feedback"

There is a workaround to use an AppleScript which is custom written to collect data from one document and collect it from another.

callejularbo wrote:

I am converting from Excel to Numbers and it has so far gone well.

As you are probably discovering Numbers has a lot in common with Excel (in particular the functions) but also a lot that is different. So it doesn't always make sense to simply replicate what you were doing in Excel.

Note how easy it is in Numbers to have multiple tables on one sheet (tab). Rather than one big expanse of cells as one often has in Excel, you will find it is more efficient to work with smaller, special purpose tables. Rather than referring to ranges that are only a partial column (for example C2:C4) it is usually easier to refer to an entire column with just the column letter (C).

Because it is so easy to put multiple tables on a sheet, one has plenty of "room" to include work all in one document that in Excel might have been spread across different documents.

Highly recommend spending some time with the templates at File > New to get a feel for efficient document design in Numbers.

SG

That is what we all do. We integrate the information in different sheets of the same document

Unfortunately, Numbers is not supporting it. You may copy that spreadsheets to that file so you can refer from it