On Fri, 18 Jun 2021 09:32:44 +0100, Timothy Collinson
<xxxxxx@port.ac.uk> wrote:

[Quoting me...]

>> Briefly venturing away from base ten, we find vestiges of base twelve in
>> the terms "dozen" and "gross", representing the first two powers of twelve.
>> The term "score" comes indirectly from base-twenty usage (and modern French
>> continues to have vestiges of this; numbers larger than twenty are
>> described as x-twenties-plus-y). MesoAmerican numbers were written in a
>> mixed-base system, using five and twenty as the two bases. The
>> pre-decimalization Pound Sterling was divided using bases twenty (twenty
>> shillings per pound) and twelve (twelve pence per shilling) both.

>Yes, and aren't I glad I *just barely* missed ever having to deal with this.

Conversion, as I recall, was 1971 (so I would have had to deal with it for
e.g., candy and sports trading card purchases). But the old £sd system had
its advantages: it admitted easier calculation of fractions of the pound,
because the 240d that made up the pound is evenly divisible by quite a lot
of numbers - 2, 3, 4, 5, 6, 8, 10, 12, 16, 20, 30, 60, 80, 120, and
(obviously) 240. So if you were buying something that was 3 for £5, there
woudn't have been any rounding-to-the-penny involved, it would have come
out exact (£1 13/4).

>> One can also use a partially subtractive system, instead of a purely
>> additive system: written Roman numerals use this model; one normally does
>> not write "five plus four ones" (VIIII) for "nine"; instead, it's "one less
>> than ten" (IX). The Roman system only admitted subtracting one instance of
>> the previous power of ten from a number; one conventionally wrote
>> "ninety-nine" as "XCIX" (ten less than one-hundred, plus one less than ten)
>> rather than "IC" (one less than one-hundred).
>>
>
>ah!  and that I knew but never knew why and often wondered.
>
>One can use any of these to give the sort of foreign flavor discussed in
>> the original article, without impairing understandability significantly -
>> but they can still be enough to cause the sort of difficulty that comes
>> with making wrong assumptions...
>>
>
>And presumably everyone's seen the recent meme about Roman numerals:
>https://me.me/i/i-cant-remember-what-51-6-and-500-are-in-13639991

I'll bet that the US Marines have little good to say about their 501s...
and I'm NOT referring to casual denim wear...

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