Q:

Automatically append given text to the result from a formula

I have the following formula:
=$AF$46

How would I append text to its result?
e.g., if =$AF$46 is showing up as 0.00, how would I make it show 0.00% done?
Editor's note: The question was later extended to "restrict" formatting of the formula's result to 2 decimal places. Some answers predate this requirement; others cover either of the two possible interpretations of "restrict": "up to 2 decimal places" and "exactly 2 decimal places".

A:

Maybe just use custom formatting:  
#,##0.00"% done"  

(preserves value in case required for further calculation).

A:

You can add text via a formula like the following (if you place this in a different cell than AF46):
=AF46 & "% done"

