We are currently costing up a major house makeover for a new property that we are in the process of buying. I have set up each of the rooms as separate spreadsheets in a Google Docs spreadsheet.

I needed to bring together the totals of each sheet to combine them in a grand total.

The following is the explanation from Google Docs Help (Which helped!):

Referencing other sheets and making data from one sheet show in another

Within a single spreadsheet, you can replicate data and copy it from one sheet to another by entering the sheet name and an exclamation mark before the cell being copied. Here are some examples:

* =Sheet1!A1
* =’Sheet number two’!B4

Please note: If a sheet name contains spaces or other non-alphanumeric symbols, you’ll need to include single quotes around it (as in the second example above)

Simple!