When you protect a sheet in Excel many icons are turned off (greyed out), including the ever popular AutoSum icon. That’s when it pays to know keyboard shortcuts.
In the image below the AutoSum icons are greyed out.
To easily insert the SUM function in an unlocked cell in a protected sheet use Alt + =
This will insert the SUM function with an estimated range or the formula
You can then use the mouse to select or change the range to include.
This shortcut can be used anytime and is useful to know.