Roy Smith wrote in
:

In article ,
Judah wrote:

I absolutely agree... I was just answering the question of why the
math "trick" works.

In flight I can't think about Math - I have to concentrate on things
like remembering whether I am coming from the East or the West!

Oh, that's easy. Fly at 4500 and call up ATC for flight following. If
he yells at you about your altitude, you know you're coming from the
West.


Whenever I call up ATC and mistakenly tell him, "I am 10 miles West of HPN
at 4500", he always seems to get tense and tells me to ident..