Hi j'
When discussing Numbers, "Spreadsheet" and "Document" are both short forms of "Spreadsheet Document", and refer to the whole document, which can be saved as a single file. Numbers provides no mens by which one Document can access the data on another Document.
One Numbers Document can contain several Sheets. Each Sheet is a large 'canvas,' on which can be placed one or more Tables (and/or other Objects.
Using Numbers, you would place the prices on Table A, and use one or more Tables (B-Z) containing a combination of the data and formulas needed to lookup the required data on Table A and make the calculations needed for the estimates on each of Table B, Table C, etc. Each of these 25 tables may be placed on a separate sheet, or two or more may be placed on a shared sheet.
Results (on, for example, Table B) would change with a change of data values (on Table A). Numbers recalculates automatically when there is a change in data, which may make your proposed 25 tables accessing the lookup table somewhat time consuming, depending how many formulas are involved each time there is a change on Table A.
For a simple example showing calculations on one table using data on a second table, take a look at the Personal Budget template that came with your copy of Numbers. All day to day data entry (plus some calculation) is done on the Transactions table, while the Summary by Category calculations are done on the table with that name, located on a separate Sheet in the Document.
Regards,
Barry
