You can absolutely do this.
You can reference any cell anywhere in the spreadsheet using the format:
=Sheet Name::Table Name::Cell Range
Additionally, you only need to specify as much as you need - for example, the Cell Range:
=A2
is read as A2 in the current table, since no other table is referenced.
If you want cell A2 from a different table, just prepend the table name:
=Other Table::A2
This will reference the cell A2 from the table Other Table,
One variance here - In this case Numbers will look for a table called Other Table on the current sheet. If it finds one, that's the one it will target. If there is no Other Table on this sheet then Numbers will look through the other sheets to find a table with that name. As long as there is only one table in the entire document with this name, Numbers will find it.
If there are multiple tables with the same name, you need to prepend the sheet name so that Numbers knows which Other Table you're after:
=Data Sheet::Other Table::A2
This unambiguously identifies the cell A2 from table Other Table on the sheet Data Sheet.
Again, you only need to add as much detail to identify the cell you want, so ordinarily you can nix the Sheet Name and Table Name elements, but they're always available.