As others have said, you can't generally use the word number to mean count. That is, you can't say "Location number: three" to mean "There are three locations".
There does exist one specialist, specific instance where number does mean count: in inventory listings.
- Screws, large, 24 number
- Screws, small, one gross
It's not very common, and it is rather old-fashioned. It's probably used to ensure that the meaning of 24 [in this case] is understood as a number of items rather than anything else, and could be a contraction of in number.
For your locations example, you might be able to use "24 in number".
[In such listings, off is also used to indicate the number (the phrase "one-off" is still current), but I have seen number used in this way.]