Hi Jim
A comment box isn't a good place to hide something because cells containingcomment boxes get highlighted. If you are looking just to copy and paste a formula into a Comment box then just Copy and Paste it in, I tried to get it to paste in the results but that didn't work perhaps you could convert it to text before you paste it over.
A better solution to 'hiding' something would be to go to Format>>Cells>>Protection and check hidden then go to Tools>>Protection.>>Protect Sheet enter an optional password and your formulas will be hidden.
HTH
Dave