Is the function n divided by 3 one to one and onto?

Answer 1

This depends on how you define your domain and codomain. f(n)=n/3 is one to one and onto when f is from R to R, but if we define f: X --> Y, where X = [0,3] and Y = [0,3], then f maps [0,3] to [0,1], so f is not onto in this case.