One way:
To reset all toolbars, you can delete (with XL closed) the
~:Library
references:Microsoft:Excel Toolbars
file, where ~ is your home directory. Restart XL and you'll be able to
see the toolbar.
Alternatively, to just make the Formatting toolbar visible, you can
switch to the Visual Basic Editor (Opt-F11 or Tools/Macro/Visual Basic
Editor), open the immediate window (CMD-G or View/Immediate Window) and
paste or type these lines, following each with a Return:
Application.CommandBars("Formatting").Enabled = True
Application.CommandBars("Formatting").Visible = True
Type Opt-F11 to return to XL.
Just FYI, you can find Mac-specific XL help in the
microsoft.public.mac.office.excel
newsgroup.