Data changes result in recalculations of totals which are not always visible, depending on your spreadsheet layout. To keep an eye on how these totals are being affected without dashing around your spreadsheet, collect the important totals into a Watch Window. You can then see the collective effect of your new data from wherever you are in your file.
To add a cell or cells to this window, select the Formula tab, Watch Window, and click the Add Watch button. Select the cell or cells to be watched and click Add. Continue by adding others in the same way.
Whilst everyone is changing from the old 2003 version of Excel to the new 2010 version, some people will still need to provide spreadsheets in the older version. If this is for a single or occasional file, in the Save As dialog box simply change the File Type in the bottom box to Excel 97-2000 Workbook, beneath the File Name.
If you are saving in the old format on a regular basis, it will be simpler to change the default file format. Click on the File tab and select Options, and on the Save page, change the default File Type at the top. When everyone is converted, change this back to Excel Workbook.