I'm having a difficult time understanding the use of の-Adj in the JLPT N5 grammar examples and practice I've been studying and haven't found a good resource for finding the answer. The sentence is fairly simple but I can't tell what the purpose of the の at the end of the Adj is in it. It goes:
大きいのは いくらですか。 Ookii-no wa ikura desuka?
Does anybody have any clue? Thank you!
の in this case is a pronoun that can be translated to English as "one".
(More precisely, it's a "dependent indefinite pronoun")
Therefore:
大きい = "big" (adjective)
大きいの = "big one" (noun equivalent)
By applying this translation, we can see the problem that happens if we don't use の:
*大きいはいくらですか = "how much is the big" (wrong)
大きいのはいくらですか = "how much is the big one" (correct)
For more research on uses of の, I recommend reading the relevant chapters of the book "A Dictionary of Basic Japanese Grammar".
According to "A Dictionary of Basic Japanese Grammar", page 318:
の: a nominalizer which is used when the nominalized sentence expresses a directly perceptible event. (...)
Example sentence(s):
日本へ行くのは簡単です。
Going to Japan is easy....
Formation:
話すのは
The act of talking高いのは
The expensive one静かだったのは
The one that was quiet...
の makes a noun equivalent from a sentence.
...
There is another nominalizer こと. の and こと are sometimes mutually interchangeable. For example, [日本へ行くのは簡単です。] can be restated as:
日本へ行くことは簡単です。
Going to Japan is easy.
