What a good comeback for this?

At my math table, I always joking say “if my calculations are correct...” and It drives my friends crazy. Once I put in my calculator “Anna is cool.” (our calculators can type words and I’m Anna btw) my friend pressed enter, and it said error. So ever since, that was our inside joke. I took a picture of my math table with our calculators, looking crazy. (on Facebook) and for the caption I wrote “If my calculations are correct” and my math teacher wrote as one of the comments “error”. What something good I can say back?