This is surprising to me because as a British person living in the US, who is familiar with British and American English, I've never once heard anyone use "and" to mean a decimal point. Literally never. The first time I'm hearing about it is from your comment.
It’s a distinction I remember from (American) childhood (I’m ~40) but I think even then it was viewed as pedantic and falling out of common usage. I don’t think either is “right” even if I take a prescriptivist approach, but even if I’m not aware of it I do tend to favor omitting non-decimal “and” in my own usage in hope it’s less ambiguous.
And just because it exists, doesn't mean it's "right".
Your link is the only one I could find on the first page of google that states "and" means decimal point. Every other source I could find says "100.17" is either "one hundred point one seven" or "one hundred point seventeen".
I'm not sure where "one hundred and seventeen" would mean 100.17. To me, as someone from the US, it unambiguously means 117. I probably wouldn't use the "and" myself, but it makes no difference in interpreting the numbers. To say 100.17, I would say "and 17 hundredths", not just "and 17" (17 what?).
imagine you are reading lists of currency amounts off to another person across the room going over ledgers. It's an easy shorthand to adopt to compress more information into the bandwidth. And if you adopt it as a way of speaking every day, you don't need to talk about it any more.
I think people are forgetting, before the days of numeric calculation by machines, there were rooms full of people tasked with keeping track of these things.
I'm not saying "I'm right", I'm saying "this is a system I was taught, the system pre-existed me, and I thought an intellectual website that obsesses over the history of small details and unambiguous communication protocols would appreciate my contributing it."
back when we wrote checks, you didn't write the word "and" till you got to the cents (US) on a line that was preprinted "dollars": one hundred fifty three cents dollars" vs "one hundred fifty and three cents dollars".
It's history, it's interesting, it's not meant to throw you into a panic or fits of anger. And I very much doubt that you speak for all of English speaking countries, and through history as well, but must admit you might and I'm lucky to encounter an historian of numerical orthography.
like 5 dollars and 13 cents, which still wouldn’t express a decimal point
it doesn't express a decimal point if you think of cents as a completely different unit of currency from dollars, but if you think of cents as 1/100ths it actually does indicate the decimal point. "5 dollars and 13 100ths" which is what cents means, and which is sometimes used when not referring to money, for example items that are measured in centiles such as interest rates. I think our forebears were more likely to throw words like centile around, and thats how they came up with the word cents.
My cousin is Italian and he always says "for cent" to me and I scratched my head till I realized, per is translated to for from Italian, and they say "25 per cento" so he's just translating it to English as it makes sense to him, not realizing we also have the word per.
Your cheques example is a completely different matter because you’re specifying a unit, without which it would be nonsensical in at least most English locales (all that I know of). That dividing “and” in {{N dollars} and {N cents}} is just a normal “and” like any other in English, roughly meaning “plus”. In Australian English, I would pronounce $1,234,567.89 as “one million, two hundred and thirty-four thousand, five hundred and sixty-seven dollars and eighty-nine cents”.
For more interesting currency matters, go back to https://en.wikipedia.org/wiki/£sd#Writing_conventions_and_pr..., where you had three items, and “£2/4/6” would typically be pronounced “two pound, four and six” (or sometimes “two pounds, four shillings and sixpence”). This shows more clearly that what it’s a perfectly normal “and” like any other in English. (Also that conventions can certainly allow elision in understood contexts. I’ve never heard of “one dollars and twenty-three” for “$1.23”, but it would be consistent with the sorts of shortenings that sometimes happen.)
my tone was probably a bit blunt. It seems to be a stimulus-response in me when regional differences in language, date formats or units of measure are presented as being wrong rather than just different.
the sense in which one way is "wrong" is the same sense in which the oxford comma is argued: nobody is saying that civilization will collapse either way, but one way is tighter in terms of eliminating more common forms of ambiguity. And when saying 150 is one hundred and fifty, the "and" adds nothing in terms of information or comprehension; to that very same person, "one hundred fifty" is just as comprensible.
and fwiw, I don't think it's a regional difference, I think it's a difference between certain traditions within the banking and accountancy areas, vs outside.
