I was told that Danish made exactly the same change in counting. When I spent a summer in Denmark in 1970 a friend of mine told me that people under a certain age, something like 40 or 50, said femti fem for fifty five (I may get the details wrong since it is all from 35 year old memory), while the older ones said fem og halv tres (literally, five and halfway through the third twenty). I assume Norwegian was similar and you can see why they wanted to change it. The 50 crown note said femti, incidentally, not halv tres.
I think even in German, where fifty five is a more logical fuenf und fuenfzig, it is still provably confusing. And English must once have used a similar system. “Four and twenty blackbirds”, “four score and seven”. The latter was certainly an archaism in 1863, but not so much as it is today. The only way to change such a system is to change it, there are no halfway houses.
I don’t know how Sweden counts, but imagine what they went through in the early 60s when they changed from left hand driving!
It may have been the children’s text, but it was in a small volume containing basic Old Norse grammar along with some short sagas and a few maps, with the grammatical explanations being givein in English. It all started my lifelong fascination with the history of Greenland and how the midiaeval colonies died out.
No, Norwegian never had the Danish base-20 system. And although I don’t know when they started using forms like femtifem, I do know it’s still common to use the “base-20 tens”. Or maybe that’s just when the customer is Norwegian.
