In the same way that it's necessary to include both 'colour' and 'color', this will only work for both countries if we have 'one thousand and one' and 'one thousand one' as acceptable answers. I've never heard anybody in the U.K. say the latter so this will keep coming up otherwise.
British English isn't exactly a dialect... And there's really only two main spelling/style types: US English and Commonwealth-descended English. As far as I know, most of the English-speaking countries outside of the US generally follow the UK/Commonwealth style. Suggestion is to recognise that the US is not the only proprietor of English, nor is it the main one.
Can I clarify? The notes say that le is used at the hundreds level (i.e. there is nothing in the 10s column). Here, though, there are no hundreds. It sounds as though le is used when other columns are omitted (including the hundreds). Is that right? E.g. would there be (one or more) "le"s in 100104? Thanks
You rather mean tens (10s) digit, right? The Native Vietnamese:
100 một (1) trăm (100)
1'000 một (1) nghìn/ngàn (1'000)
10'000 mười (10) nghìn/ngàn (")
100'000 một (1) trăm (100) nghìn/ngàn
or the Sino Vietnamese and mixed morphemes:
1'000'000 một (1) triệu (million)
10'000'000 mười (10) triệu (") 100'000'000 trăm (100) triệu
1'000'000'000 tỷ (milliard/billion)
and their following numerous are fixed expressions.
0 -> không • linh/lẻ (none) The foreign-language borrowed word zêrô (zêro, dê-rô) is often used in physics-related publications, or colloquially
101 -> một trăm linh/lẻ một (linh/lẻ being used as zero tens digit markers) Although linh is the standard form, it is more commonly used in Northern Vietnam, lẻ in the South
1'001 -> một nghìn/ngàn không trăm linh/lẻ một When the hundreds digit is occupied by a zero, these are expressed using không trăm (no hundreds)
For further information: https://en.wikipedia.org/wiki/Vietnamese_numerals