As has been noted many times, imported text often has apostrophes at
the beginning of each cell.

Firstly, how can one get rid of it? The Help menu says "uncheck
Transition Navigation Keys", but this is already unchecked and makes no
difference anyway. Doesn't anyone ever edit help menus? Was this
pasted in from the help menu of some other application?

In the end I saved as CSV, opened it again and saved as Excel without
the apostrophes, but opening CSV from Excel causes all kinds of
problems unless the whole thing is very simple (and has no dates).

Secondly, my problem arose when I wanted two columns of numbers sorted
in the same order, one in general format and one with apostrophes. It
didn't really matter which order as long as they were the same.

When I changed the format of the apostrophe fields to Number, they
remained untouched of course.

When I changed the format of the number fields to text, I expected them
to sort in alphabetical order, but they remained in numerical order.
How does one control the sort order in Excel? It isn't among the
options, like day of the week etc.

This is the opposite of another situation I had where dates kept
sorting in alphabetical order despite being in date format.