This is a great question. I can only truly speak to the Mathematics piece, but I know in a lot of my Mathematics courses in college I was often with many Computer Science majors.
The truth is Mathematics is so much more than what people think and realize. Every class that you take is more than numbers or solutions, it's about processing what's in front of you, questioning the task, analyzing what you know and problem solving many potential different scenario's. You become detail oriented, organized, and methodical, while also trying to determine the best course of action for the situation at hand. Mathematics gives you an understanding of figuring out different ways to think and process tasks, which is incredibly beneficial to you as well as many employers.
There is a book called "101 Careers in Mathematics" I suggest you read, which my adviser in college pointed me to read as well. This will give you an idea of the endless possibilities that Mathematics opens the doors to. I would recommend thinking what interests you and what excites you when you think about your career.
I would imagine having a Computer Science major/minor only adds more value to you.
I hope this helps!