4. Our map of the downtown area made locations more clearer for my visiting uncle.
Incorrect, we should never use more/most with -er. We use more/most when a word is 3+ syllables. Since clear is only one syllable, we should use -er. Therefore, the sentence should read, "Our map of the downtown area made locations clearer for my visiting uncle.
5. Our city has a more interesting history than any city in the state.
Incorrect, we use more when we are comparing two things to one another. When we compare 3+ things, we should use most. Since, we are comparing one city to all of the other cities in the state, we should use most. The sentence should read, "Our city has the most interesting history of any city in the state."
6. Our city is more picturesque than most other cities its size and age.
Correct. Even though this is a bit confusing based on my explanation from #5, it is correct to use more in this case. It would not make sense to say "Our city is most picturesque than most other cities its size and age."
