So you agree with the second sentence of my post, then? 
The arguments in favour of ‘easier reckoning’ disappeared anyway when calculators came along to do the number-crunching for you. Computers could have been programed to cope with £.s.d perfectly well in the 1960s. The government just didn’t want to.
But calculators work in decimals too. You’d want a specialised currency one to work out, say, 17% VAT of a pound.
Giles, your maths is excellent. 
But having to list all the coin values as you do, plus mod 12 the pence proves that aldiboronti was wrong to say the maths was easier with duodecimal!
It is a problem. That’s why we have informal conventions like “80K” and “30 grand”, and sllghly more formal conventions like those employed by accountants who will draw up columns of figures witn a note to indicate that every figure in the column represents either 1,000 or 1,000,000 units of currency. These issues are magnified if we have to employ such conventions when discussing the price of everyday items like soap or matches, rather than occasional purchases like cars or houses.
When you think about it, the fact that we have developed such conventions for dealing with large amounts, but not for dealing with small amounts, suggests that our basic currency unit is too small, rather than too big.
Now you’ve got me really curious, but this will be a question for American dopers with kids. Are the times tables still taught here up through 12? As a child in the 70’s, we had to memorize the times tables through 12 as well. Soon afterward we learned how to multiply any arbitrary length numbers (as someone pointed out to me here, they teach that differently these days, too), which point having learnt the 11’s and 12’s by rote seemed rather stupid and redundant and arbitrary. Why not 13? Why not up to 14?
Now I’m suspecting that there was no reason at all to learn up through 12, other than because of some carryover tradition based on UK currency?
Man, this is almost a Cecil-worthy question: why do (did) we have to learn the times tables up through 12?
One of the pithiest posts I’ve ever seen. Thanks Glee.
Or inches in a foot. Or anything involving dozens, e.g. most elementary school kids need to work out how many bottles of wine in x cases.
Hardly. It is still relevant to want to have a currency where you do not need a calculator. Who takes a calculator to the store with them?
Does any country not use decimal currency today? I vaguely remember reading something abount Myanmar/Burma have a base 9 currency.
Nope. 1 kyat = 100 pya, at least today. I actually remembered that the Saudi rial was 20 of its smaller unit at one time. It’s 100 hallallah today. Wiki has a list (of course):
Madagascar and Mauritania have a unit of currency divided into 5 of the smaller unit, and one of the articles mentions that they are the only two non-decimal currencies today. I think you’ll find that a lot of countries used to have smaller denominations that weren’t powers of ten.
For when they go to the liquor store?
My understanding is that memorizing up to 12x12 is a holdover/downgrading from earlier generations having to memorize up to 15x15 or even 20x20. Nowadays, there are too many other things to teach, so they don’t waste time with that.
Indeed, but I was just addressing the comment as to whether learning 12x tables was because of UK currency by giving other examples of base 12 usage.
You may be vaguely remembering the fact that in the 1980s, Burma briefly had 15, 35 and 75 kyat banknotes.
You can add in Azerbaijan (5000:1) and Poland (1000:1) to the list.
I dunno how “common” it was, but when I was in Paris in '08, receipts at some restaurants I went to had the total in both euro and franc (I believe the more recent franc, however).
Do you mean not use base 10, or not use decimal points? If the latter, then people have already mentioned the S Korean won and the Japanese yen. In Japan, they use long scale counting, meaning they have new number names at 10,000 and at 100,000,000, rather than at 1,000,000 and 1,000,000,000. That is to say, after one, ten, hundred and thousand, they have a new word for ten-thousand. They then count up to 1000 ten-thousands before giving a new name to what we call hundred-million.
The yen is roughly equivalent to a US penny, so the ex-pats here just think of a hundred yen as a buck. They even have hundred-yen shops 
In areas that use feet and inches, you can get specialized construction calculators that handle yards, feet, inches, and fractions of an inch. They also handle slopes and such, as calculating roof lengths. I almost bought one at the hardware store yesterday, but it was a little expensive; it cost around $84-13/16.
In Mauritania, 5 khoums make 1 ouguiya
In Madagascar, 5 iraimbilanjas make 1 ariary
Last time I was there, there were 1000 Mils in a Tunisian Dinar.
In India they used to learn the 16 times table because there were sixteen annas to the rupee (don’t know if they still do). In my father’s office in the 1970s they had an Indian engineer and neighbouring colleagues would often ask him “what’s fourteen sixteens?” or some such, in the days before desk calculators became common.
They had mechanical adding machines in the accounts dept which would up and subtract in £.s.d. (possibly even multiply, hard to remember)
There was nothing particularly hard about £.s.d. accounting, like most things, if you’d never known any different you just accepted that that was the way things were and got on with it.