I’m an American teaching English overseas using British text. I want you opinion on how to pronounce numbers.
English English: I include the ‘and’, though normally just as a ‘n’ sound rather than a full word unless I’m trying to emphasise the following word, as does most of the country, in my experience.
aaand…the ANDs are two for two!
Let’s press our advantage while it’s Western Hemisphere Night 
What he said. 
One oh five.
A hundred and five.
Think about the difference between
One hundred five pence
and
One hundred and five pence.
The former counts £5 of currency; the latter £1.05.
I don’t use “and” - I recall a teacher being very firm that the “and” indicated a decimal place.
I’m from UK and I’d say “one hundred [barely perceptible noise] five”, but putting absolutely nothing between the “hundred” and the “five” would be unacceptable and weird. I would obviously write “one hundred and five.”
US. I usually use “and” (really, “n,” like Filbert), but not always. “One hundred five” sounds grammatical to me as well, but I associate it with official or scientific situations. Like, some technician counting off seconds into a rocket launch.
I’m English and it’s one hundred and five for me. One hundred five is certainly understandable and acceptable but sounds American.
I say “and” but I don’t write it (on checks, for instance.)
This. It indicates that a non-integer quantity follows. Imagine the quantity is instead 105.3125; it gets messy if you say “one hundred and five and five thirty-secondths.” Just leave out the first “and”.
Why would you not just say “one hundred and five point three one two five”? Simples.
Or for a simple fraction like 105.5 “one hundred and five, (pause) and a half”
+1
Or
one oh five point three one two five
one oh five point five
People keep saying this in threads like this, and it always baffles me. I have never, in my 50 years on this earth, spoken a decimal aloud as “and,” nor have I ever heard anyone else do so, nor has any teacher ever told me to do so.
A decimal is read aloud as “point.”
Yes, I use the word “and” when reading numbers. 105 is read aloud as “One hundred and five.”
American pronunciation - uh hunderd n five
Why would you? What is the grammatical purpose of uttering “and” after the hundreds?
For that matter, imagine I have a longer number, like 179,432.16. Why are you only putting an “and” after the hundreds? Why not say “one hundred and seventy and nine thousand and four hundred and thirty and two point one six?”
Sorry for muddling my point by presenting the non-integer part as a decimal. Imagine instead that I had written"105-5/16".