Integers with leading zeroes

[Laura Creighton]

In a message of Wed, 22 Jul 2015 12:10:55 +0300, Marko Rauhamaa writes:
>My native Finnish luckily has distinct words for the two things: "luku"
>(a quantity) and "numero" (a digit, numeral or label):
>
>   luonnollinen luku (natural number)
>   kokonaisluku      (integer)
>   rationaaliluku    (rational number)
>   reaaliluku        (real number)
>   kompleksiluku     (complex number)
>   liukuluku         (floating-point number)
>   desimaaliluku     (decimal number)
>
>   puhelinnumero     (telephone number)
>   rekisterinumero   (registration number, license plate number)
>   tilinumero        (account number)
>   huoneen numero    (room number)
>   sarjanumero       (serial number)
>   tuotenumero       (product number)
>
>Obviously, the words "liukuluku" and "desimaaliluku" slide into the
>realms of numerals, but nevertheless, they deal with quantification
>rather than identification.
>
>
>Marko

What I want to know is why is 'huoneen numero' 2 words?

Laura