Which form of adjective should be used? [duplicate]

Question

In the following sentence which form of the adjective should be used?

There were three four rooms in the hotel, the smallest/the smaller of which served as the gym.

I think it should be the smallest because the comparison is being made between more than two things.

Answer 1

There were three [to] four rooms in the hotel, the smallest/the smaller of which served as the gym.

To make sense of the sentence, I have added a 'to'. With that, 'smallest' is right; the comparison is being made among more than two things.

Answer 2

Your sentence, as it stands, does not read well. I think this should be either:

There were three to four rooms in the hotel... (really small hotel though!)

or

There were three four-room suites in the hotel...

But to answer your question, I suppose this is what you are looking for:

There were three [to] four rooms in the hotel, the smallest of which served as the gym.

Here for instance you can find a summary of comparative and superlative adjectives.