robdesbois
Rob, I have applied that method all the way through highschool and it works really well. You only have to remember one additional thing: if there's any kind of circular motion involved, you usually have to add 2*pi. (When going from RPM and torque to power for instance.) I learned that the hard way...
I wonder if Einstein used this method too to derive E=Mc2?
Oh, and obviously this only works with number from the SI standards. With miles, feet, pounds, stone, inches, gallons, knots, horsepowers and so forth all bets are off!