Why do I keep getting bad grades from the subjects that I'm very good at Okay, I'm an economics student at one of the highest ranking universities in my country. I have 3.9 gpa and I'm also double majoring with mathematics, just started double majoring this semester. 

After double majoring with mathematics, everything has changed pretty much. I'm taking a real analysis course in mathematics, and I have one of the top scores in real analysis course. But I can't say the same for economics courses. So here is the thing:

Economics courses is made out of mathematics pretty much, it's just the application of mathematics to the real life. I don't like economics, I actually don't want to study it, I want a career in mathematics, but that doesn't mean I don't study to economics courses.

I study them to, and topics seem too easy to me. I pretty much enter every economics exam knowing everything, I never leave a blank or anything. I solve every single question and I'm 100% sure what I'm doing. But I take incredibly bad grades, just because of the calculation mistakes I do. It's not because I didn't solve the question or anything, it's just because of the calculation.

I still don't get it though. I can't change this, I wasn't doing this previous year, It started this year, and some people relate it to the hardcore analysis course I'm taking. Some people think that's why I fail at practical economics courses, because I've started to think more "mathematically"

By the way, by bad grades I mean like 30/100 in an exam which has an average 65/100, all mistakes made because of failed calculations.

I seriously don't know what to do? These failed economics grades will let my gpa down and will make it harder to get an acceptance to a good grad school. Plus, they also let me down motivation wise, hardly.

I don't know what to do and how to overcome these kind of mistakes I do. But I know that I don't want to study economics. + It's hard to change majors here
But I take incredibly bad grades, just because of the calculation mistakes I do. It's not because I didn't solve the question or anything, it's just because of the calculation.


Boy that word "just" is dangerous, isn't it?

The unfortunate truth is that you are not good at practical economics, precicely "because of the calculation mistakes that you do".  You don't think those mistakes are important (hence "just"), but you don't get to decide what is and isn't important in your classes/research/work. The people who evaluate you get to decide what's important.

There are many disciplines where the primary goal is to get the right answer, not to demonstrate your "understanding". It doesn't matter whether you grok the theory if you can't actually execute on the fine details. If you didn't get the right answer, you didn't solve the question.

This does not mean that practical economics is less worthwhile than hihg-level mathematics, which cares less about arithmetic skills.  It only means that practical economics is different.  Math emphasizes different details that  you're more comfortable with and that other people would find boring and/or baffling.


  I can't change this


Of course you can.  You can do exactly what everyone else does to become good at anything uncomfortable: Put on your grownup pants and practice, fail, listen, practice, practice, fail, listen, practice, practice, practice.