I do not have a mathematical degree. What I do have is a Bachelor of Science in Physics from Vanderbilt University. However, mathematics is one of the few areas where people within the field tend not to be impressed with such a thing!
But it does mean I have some college level mathematical training.
However, my focus is on relatively simple mathematics requiring basic concepts, which requires what are usually called elementary methods. That means functionally that most of the time you only need simple mathematics like basic algebra, including modular arithmetic to understand what I'm doing.
There is some research requiring calculus, but it turns out that calculus is one of those mathematical areas where physics students get LOTS of training, so I have a firm background in it. And actually taught myself calculus when I was 12 after I read that one of my heroes Albert Einstein, of course, did so when he was 12.
I've had extensive training in problem solving since I was a kid, including some time at Duke University. Guess it's worth backing that up with a certificate:
It has been new to me to be challenged by others as much as I have been when it came to discussing mathematical subjects. Most of my life people have been, let's say, less inclined to challenge me in such a way. But I think it has been healthy for me to back things up by other means.
To me the focus on basic mathematical tools is most important as it allows interested people to easily check my work. But guess if it helps it is worth it to put up other information that can be helpful.