In Excel 2010 or 2007, if you want data from one worksheet to be linked to, or shown in another worksheet then follow these steps:
1. In the sheet you want to link to (source) select the cell where the value is stored.
2. Right click and select Copy.
3. In your main sheet (target), select the cell where the value is to be displayed and right click on it.
4. In the displayed context menu, under Paste Options, click on Paste Link (the last icon to the right).
5. The value in the source sheet will now be reflected in the target sheet. Notice the link to sheet1 in the formula bar.
6. Every time the source sheet is updated, the target sheet will also be updated with the new values.
7. The same procedure can be applied to link to data in another workbook.