what is the oxidation number for nitrogen in the following?

Question

NH3
NO2 1-
N2
NO2Cl
N2H4

We will be happy to critique your thinking or work.

I don't even have a clue as to how to work it out.

Answer 1

For NH3 is -3, for NO2^1- is +3, for N2 is 0, for NO2Cl is +5, for N2H4 is -2