1. The problem statement, all variables and given/known data floor((n+1)/2) Find whether this function is 1-to-1 and/or onto from Z to Z. 2. Relevant equations 3. The attempt at a solution This is not one-to-one because f(1) = f(2) = 1. Regarding onto, we need to show that f(a) = b floor((n+1)/2) = b 2b = n + 1 n = 2b - 1 f(2b-1) = floor((2b-1) + 1)/2) = floor(2b/2) = floor(b) = b. I'm not sure how to take the floor function into account for my onto calculations.