is it a general rule to have の following a number?
Seems all the textbooks I use show this.

ie. 日本には､ ４７の都道府県があります。 There are 47 prefectures in Japan.
what if you remove the の? ４７都道府県があります。 Is this still correct grammatically?

Or how about this situation:
日本の四つの大きな島を行った.
can we remove the の after the 四つ?
日本の四つ大きな島を行った.
or do we always have to put a の after the number? just hard to see the sense of "belonging" with a number.

thanks

At first it looks fairly simple to count in Japanese, but it turns out to be rather difficult because of the counters.
Search on counters.
Those の, however, is something different.
You certainly don't always to have to put の after the number.

In Japanese numerals cannot quantify nouns by themselves (except, in certain cases, for the numbers from one to ten).
For example, to express the idea "two dogs" in Japanese one could say 二匹の犬 ni-hiki no inu, in which 匹 ("hiku") is the counter for small animals, and the の is the same kind of の as in "nihon no inu".
Also possible is 犬二匹 inu ni-hiki. In that case there is no の.
However, just pasting 二 and 犬 together in either order is wrong.

The の here is not possessive (or "belonging"); it's descriptive. XのY generally means that Y is described by X. The possession/belonging particle is a separate thing.

hkoros Wrote:what if you remove the の? ４７都道府県があります。 Is this still correct grammatically?

Yes. Numbers work as an adverb by themselves.

Quote:Or how about this situation:
日本の四つの大きな島をに 行った.
can we remove the の after the 四つ?
日本の四つ大きな島をに 行った.
or do we always have to put a の after the number? just hard to see the sense of "belonging" with a number.

Yes, that の is necessary. It can't be an adverb in that position.

ok thanks all, makes sense.