GPA Addendum

Hiya!

Newbie 7sager (?) and first-time poster here. My question is regarding GPA addenda. The general advice, I see, is to write one to explain an upward or downward trend in one's GPA. What happens if one's GPA was all over the place? I was an Econ and Math major. I ended up hating Economics, and my grades in my Econ courses reflect that. I loved Math, and those courses, for the most past, saved my GPA (3.42). How do you recommend I go about explaining this in my addendum? Should I even bother with an addendum at all?