Sometimes you will hear people refer to four digit numbers in terms of hundreds. For example, sometimes people will say fifteen hundred when talking about the number 1500. Is this proper?
What are the rules of usage? In my personal experience, the hundreds notation is common for values less than 2000, but rare for larger values. Can I refer to 7300 as seventy-three hundred?
I know this has been discussed in another question, but that was in terms of years. I'm asking about numbers in general.
This usage is informal but not incorrect. I wouldn't use it in official business documents, but it can be freely used in speech or less formal contexts.
While statements like "seventy-three hundred" are rarer than their equivalents for numbers below 2000, they're perfectly intelligible and frequently used.
I work in a building at '4400 North First Street'; I'd never say anything other than 'forty-four hundred' for the address.
It is perfectly grammatical, and often very sensible.
It is certainly proper grammar. From my experience, referring to four-digit numbers in the hundreds is more common in the US than in any other English-speaking country. As for 7300, seventy-three hundred is perfectly correct to say. It really all boils down to the speaker's choice. I must add, though, that for those numbers with three zeroes, thousand is preferred to hundred. Thus, 3000 is better called three thousand than thirty hundred!
I can't exactly answer but I can add that Steve Jobs is often heard talking about numbers in that way during his public keynotes. So I would say that it is proper business practice, at least orally.
In some places, city blocks are always referred to in terms of hundreds. For example, in Chicago it is normal to hear somebody talk about driving from the twelve hundred block to the seventy three hundred block of some street. This means going from a block with addresses of 1200-1299 to a block with addresses 7300-7399. It only works in cities with a regular grid layout where each street covers a range of exactly 100 addresses, but in that case the "hundred" is the basic unit, rather than the individual addresses themselves. So, you can sort of think of twelve hundred being grammatically analogous to twelve kilograms or twelve apples.
In general, I never encounter it in formal written documents. The only time I see it in writing is when somebody wants to explicitly capture a speaking style, such as an exact transcript, or dialog for a play. However, when reading a document out loud which says "7300," it can sometimes be idiomatic to pronounce it as seventy three hundred instead of seven thousand three hundred. ("Our Chicago office is located on the seventy three hundred block of Wabash street.")
I worked for a bank for 16 years. We were taught that for writing checks, for an amount of $1200, the textual amount should be One thousand two hundred, not twelve hundred.
Not that Jeopardy! is the ultimate authority on such matters, but you can hear the "XX-hundred" format used four times in just over 30 seconds in this video clip – twice by the contestant, and twice by the host.
Clearly there's nothing wrong with this usage, and, in some contexts, it simply rings and flows more naturally than its "X-thousand, Y-hundred" counterpart.
