I'm afraid they have taught a poor lesson then. In a traditional letter, the writer's own address goes in the top right-hand corner, the recipient's name and address goes one line lower but on the left-hand side of the letter, followed by a line break, then the date the letter was written, then a line break, then "Dear Sir/Madam/name of recipient". Bear in mind, I learnt letter layout in the early 1980s so things might have changed and, as you say, when an email is used, the same layout is not used.
Below, I've tried to recreate what a formal letter would have looked like when I studied admin/typing.
125 Smithson Avenue
Mr A Wilson
26 Heron Drove
23 April 1981
Dear Mr Wilson
[Main part of letter goes here]
[Space here for handwritten signature]