Question

1. He is not our age.
2. He is not of our age.

(Does #1 come from #2? Is 'of' omitted in Sentence 1?)

3. Who is a math genius?
4. Hana is.
5. Hana is a math genius.
6. It is Hana.
7. She is Hana.

(Which ones are the answers to the question, #3?)

Answer 1

1 is correct; 2 is not, unless you mean that he and we don't live in the same era!

3 - 6 are correct; 7 is grammatically correct, but very awkward and not used.