Not included in that article (but, Suzanne tells us, in a more recent
article) is perhaps the simplest way: in many fonts (but not, as it
happens, Times New Roman), there is a Unicode range called
Superscripts and Subscripts, where you will find all or most of the
digits, and there's a specially angled slash for making the diagonal
line. (Superscript 1, 2, 3 are in the Latin-1 range.) Access them
through Insert Symbol.
