In reply to: The metric system is derived from real things too posted by fontoknow
A pints a pound the world around is no more meaningful tan a milliliter of water equals a gram.
Memorizing conversions it's time better spent on basic computation, or reading or even doodling.
Rods and chains weren't arbitrary, they were derived from actual tools used by surveyors to measure property. They were the opposite of arbitrary; they were organic.
What they were was cumbersome, which was a different, though real, problem.
Those lengths were the very definition of arbitrary.
The French Imperial system's foot was actually 1.066 ft. long.