Relations and Functions

Today in class we talked about relations and functions. We also learned that a function table is almost like an input output table and kind of is. The "x" or domain is the input and the "y" or range is the output. It took me a while to get it at first, but I'm sure I've got the hang of it now. Except the whole integers thing throws me off. Oh negatives, why are you so confusing? If only I could find the cheat sheet Mr. S gave us last year. WHERE ARE YOU CHEAT SHEET?!?!