Actually, pre-decimal coinage wasn't such a bad thing at all.
You can readily divide 12 by two, three, four and six. As someone who was a child at the changeover, I learned the old system and it wasn't actually hard. It also fitted well with imperial measures, which were/are handy human sizes (people often forget that). It's rather sad to watch my kids still struggle with fractions (in their twenties) - fractions haven't ceased to be important, but they're probably harder to properly master now, as there's less reason to practice.
There were computers doing accounting before decimal coinage. In fact the UK led the world in them, pre-IBM (
LEO1).
Later on, there was the awkwardness of doing floating point arithmetic on early PCs. I owned at least two generations of PC dedicated maths co-processors** that actually weren't very good at "doing sums." They output errors, as did many early office calculators.
Pre-decimal coinage didn't eliminate the floating point issue as 'stretching' computer power, but it wasn't the huge handicap it's often made out to be, and in daily life was handier than might be expected. If you add-back halfpennies and farthings, the fractions get even more useful, so your shilling is easily divided by 2, 3, 4, 6 & 8 (and almost 7*). Only x5 is a significant problem requiring a decimal point.
And it's convenient to pack items in twos, fours and sixes, rather than fives - wood screws, hinges, etc being good examples - who wants five hinges?
E.
(coincidentally, was in a pub quiz last night - hardly anyone knew a threepenny bit had twelve facets!)
**8087, 80287, I think also the one onboard some versions of 80386
*48 is very nearly 7x7. As there 14lb in 1 stone, it had some utility.
