Why are my functions not working on multiple sheets in my Excel workbook?

1. Ensure your function is referencing the exact sheet and cell it needs.
2. Check the syntax of your function using the Excel help menu.
3. Check that the sheet names and cell references you are using in your function are correct.
4. Save and close the workbook, then reopen it to make sure your changes are saved correctly.
5. If the functions still aren’t working, try resetting Excel to its default settings.
6. Finally, try uninstalling and reinstalling Excel.