[bara erom] 12.472.477 [bara emos]
[bara erom] 774.274.21 [bara emos]
for long numbers a pretty fast reversing mind is needed
I think you're mistaken about the flexibility of human mind. Eight digits may look like a lot, but that's really not a long string compared to an average line width, and it does not take a lot of effort for the reader to look ahead for the start of the number. And eight digits is probably the longest it gets anyway (OK, maybe 12, but a 15-digit number would be difficult to read for anyone in any language). Actually you should look at it as a cultural difference, even if it interferes with scientific notation (and if you think about it, the percent sign is a scientific one, even if a rather simple and widely used one). And I'm sure you know how natural each person can find his own culture, while others would be puzzled by aspects of it. Hey, you're Dutch; doesn't that number read something like "twelve millions four hundred two and seventy thousands four hundred seven and seventy" in Dutch? (What else do German, Dutch, Arabic and Slovenian have in common?) And yet I'm sure you would read it out loud without hesitation (OK, you might say that you're only reversing two digits at a time, but I could reply that the way I see it, they are interspersed more or less arbitrarily).
math goes from left to right but i once heard a talk about a tendency to go right - left as well (including mirrored symbols like \sum)
That's standard in Maghreb as far as I know. Arthur