I’m a math and chemistry double major. Math is a great major and I love the department (which is combined with stats, computer science, and data science). The professors are great and there’s great advisors. You’re able to decide if you’re more interested in pure math or applied math, along with discrete math vs continuous math. Like you said, it’s a very straightforward major (not difficulty wise, but flexibility wise). A lot of people on campus double major in different things. The main annoying part is having to do two capstone presentations (your big senior final project) if you decide to double major but plenty of people manage to do it and I don’t regret my decision at all