Omitting the “hundred” from the name of numbers

Question

I’m not a native, so I’ve always spoken numbers in English as our textbooks tell us to do: 452 would be “four hundred (and) fifty-two.” But I’ve recently heard natives say something like “four fifty-two” in a couple of movies. (The numbers could be different.)

Is this grammatically correct? Is it common in informal speech? What about formal speech? Can it be used in formal contexts?

Also does this usage depend on the context? Or can you use this system in any setting? I remember at least once (in the movie Get Smart) this style was used to refer to the number of a page (from a report). But I’m sure I’ve heard it in another context too. I just can't remember what.

I couldn't find the answer myself, mostly because I didn't know what to search.

By the way, I’ve been taught US English, but I’d like to know the UK usage too (in case there is any difference here).

Thank you in advance.

Answer 1

There is no definite rule specifying when hundred may be omitted in reading out three-digit numbers. The following considerations may influence its acceptability, but none of them provides a definite, clear-cut criterion.

(1) The formality of the context, as already explained in the answer by StephenS.

(2) The possibility of a misunderstanding: one won't read '452' as 'four fifty-two' if one is aware that it may be misinterpreted as 4.52.

(3) Whether the number is cardinal or ordinal or an arbitrary identifier: ordinal numbers are more likely to be shortened in this way, and arbitrary identifiers almost always are. One may thus hear something like 'room four fifty-two' in the same context as 'four hundred fifty-two pounds'. Even in a highly formal context, one would say 'Boeing seven thirty-seven'.

(4) Whether the number is between 100 and 199: a number in that range can easily be shortened by omitting one, rather than hundred, and is more likely to be shortened that way. If one doesn't want to say 'one hundred fifty-two', one has the option of saying 'hundred fifty-two', which diminishes the need to shorten it to 'one fifty-two'.

(5) Whether the number appears alone or among other numbers of the same order of magnitude: if one is reading a list of three-digit numbers or dictating the results of some measurements, one is very likely to shorten the numbers in this way. This is because in such situations a great deal of time may be saved by omitting hundred and the possibility of misunderstanding is low.

Answer 2

In informal speech, we sometimes take shortcuts when saying numbers.

Three-digit numbers can be said as 1-23, “one twenty-three”.

Four-digit numbers can be said as 12-34, “twelve thirty-four”.

In both cases, if the tens digit is a zero, you must say “oh” for that digit: 103 is “one oh three” and 1204 is “twelve oh four”.

If the tens and ones digits are both zero, you say “hundred”: 1200 is “twelve hundred”. I think I’ve read this is not allowed in BrE, but it’s very common in AmE.

It’s less common with five or six digits, but you could say 12,345 as 12-3-45 and 123,456 as either 1-23-4-56 or 12-34-56.

Do not do this in formal speech; say the full number.