I used that conversion recently in Munich Germany, when I noticed the taxi driver going 180 to 190 kph. 190 * 3/5 is about 114 mph. I was sure glad I knew how to do that conversion at that point in time. Maybe ignorance would have been bliss on the other hand. (Although the Mercedes did feel like it was just hitting its sweet spot as far as speed goes, and we were getting passed from time to time).
I’ve gotten pretty good at the Celsius to Fahrenheit conversion as well – approximately double and add 30/32. Right now at home, it is 17c – 34+(30 or 32) – 64-66f. It is close enough. Traveling around to Canada and Europe makes me do this mental calculation all of the time.
Octomatics – looks like a reasonable idea, that’ll never happen. Simply because of one of the last sentences in that link:
but habit is a strong force...and we are deeply rooted in
our decimal number system...but who knows...?
Habit is strong. It has been a long time since I’ve seen any signs in metric in the US. Probably won’t happen in my lifetime.