How do I sort room numbers that include alphabetes.

I know that sorting room numbers is pretty easy just highlight the whole
spreadsheet (control a). Sort with header row checked and proceed to scroll
down to room numbers.

The problems when you add alphabetes. The computer sees alphabetes as
distinct characters. like 209B 209 A 209C.

It is pretty simple to say 209, 210 211.

What do I do.