Excel UNDO LAST ACTION Keyboard Shortcut

Using the Undo Last Action Shortcut

Windows keyboard shortcut

 
Mac keyboard shortcut

This shortcut allows multiple levels of undo, stepping back one level each time it's used.
Discover 242 Excel Keyboard Shortcuts for Windows and Mac
Other useful General keyboard shortcuts
Display Find and Replace
Open Help
Redo Last Action
Copy Selected Cells
Repeat Last Action