- Tony, I ask the question about firkins & barrels because the average person is unlikely to ever encounter them.
In reality, most people will get by with fluid ounces, pints & gallons. Look at how the number of divisors drops.
1 gallon = 160 fluid ounces
Divisors are 2, 4, 5, 8, 10, 16, 20, 32, 40, 80 = 10 divisors
1 gallon is (very roughly) equal to around 5 litres
5 litres = 5000ml
Divisors are 2, 4, 5, 8, 10, 20, 25, 40, 50, 100, 125, 200, 250, 500, 625, 1000, 1250, 2500 = 18 divisors
But, obviously, comparing 5000 with 160 is a bit unfair. As Tony is no doubt aware, any number can be represented by multiplying prime numbers together
160 = 2x2x2x2x2x5 - 2 individual primes
5000 = 2x2x2x5x5x5x5 - 2 individual primes
In other words, both systems are equally good! But one system doesn't rely on remembering conversion factors of 20 & 8!
With weight, the average person will encounter imperial ounces, pounds & stones.
1 stone = 224 ounces
1 stone = (approx) 6000g
224 = 2x2x2x2x2x7 - 2 individual primes
6000 = 2x2x2x2x3x5x5x5 - 3 individual primes
Metric is better - and you don't have to remember conversion factors of 16 & 14!
With distance, the average person will encounter imperial inches, feet, yards & miles
1 mile = 63360 inches
1 mile = 1609344mm exactly
63360 = 2x2x2x2x2x2x2x3x3x5x11 - 4 individual primes
1609344 = 2x2x2x2x2x2x2x3x3x11x127 - 4 individual primes
In other words, both systems are equally good! But one system doesn't rely on remembering conversion factors of 12, 3 & 1760!
Shall we continue?
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