1. The problem statement, all variables and given/known data Q. Define an order relation (x,y)<(j,k) if and only if x+k<y+j 2. Relevant equations x<y means x+a=y and viceversa 3. The attempt at a solution I have no idea. To show it is equivalence relation, I simply show that it is reflexive, transitive and symmetric. but how do I show it is order relation?