1. The problem statement, all variables and given/known data Show that Q does not fulfill the completeness axiom. 2. Relevant equations "Every non empty set of rational numbers that contains an upper bound contains a least upper bound" (show this is false) 3. The attempt at a solution I've sat on this question for a few days, but I can't think of ANYTHING. I tried thinking of trying to show the opposite, to see where it would lead me. I couldn't start there. Any help JUST getting started? I understand what the completeness axiom is. I understand what rational numbers are. I have no clue how to start.