How to convert molecules to N Atoms

My chemistry homework requires me to convert molecules to N atoms and from N atoms to molecules in C2H5(NO2)3.
I have no idea what to do. For example i have to find x molecules in 7.5*10^22 N atoms?

Help would be awesome :D! Thanks!

There are three N atoms for every one C2H5(NO2)3 molecule.

7.5*10^22 N atoms times (1 molecule / 3 N atoms) = 2.5*10^22 molecules