Press Ctrl + Z immediately after entering a formula
Use Undo from the Quick Access Toolbar
Replace the formula with its result by copying the cell and pasting values
Select the formula cell and press Delete to remove it
Edit the formula in the formula bar and remove the formula text
Copy the cell, then use Paste Special > Values to keep only the displayed result
If multiple formulas were entered, select the range and press Ctrl + Z
If the workbook was saved, restore a previous version from File > Info > Version History
If needed, reopen the file without saving changes to revert recent formulas