Its a long journey, and without someone who knows what you don't, you'll end up getting stuck because math is primarily used today to gatekeep the more advanced subjects, eschewing intuition, and describing numerical patterns instead very abstractly.
You should start with mastering the basics to the point where you are able to do the calculations in your head almost instantaneously. Start with the material from a book series called The Cosmic Calculator. Digit Sums touch on modular arithmetic and cyclic groups (in Abstract Math).
Math is all about relationships, and nearly everything is built on a shaky foundation until you reach Abstract Mathematics (Modern Algebra), where you have to go and unlearn a big portion of what you thought you knew.
In this coursework you learn how math actually works, as opposed to memorizing a bunch of skills and strategies that may or may not work depending on the circumstances.
You'll also learn how to test for the fundamental properties you will need to perform operations between two differing objects.
Most hard science uses strategies to gatekeep careers using math, and the structures of much coursework are designed so that bridges get burnt, and the student is blamed and tortured until they quit.
The NEA promoted these structures. For a concrete example, the first of several of these gates is the three course series Algebra->Geometry->Trigonometry.
What goes undisclosed is grading changes from only following the correct method to pass Algebra (not getting correct answer), to correct method and correct answer (in Trigonometry).
There is a semester between the changes of unrelated material, so you can pass 1, and 2, and then repeatedly fail 3. The student is blamed for not knowing the material, and teacher may not have the resources or time to identify and teach a class that is not their responsibility, where the student should have failed the class 2 classes prior.
This is just one of several by-design stumbling blocks. The student is made to think they just aren't good at math, and the lack of agency to correct, the isolation, and the circular nature meet all the requirements for torture. This is how students get PTSD and never learn math beyond the bare minimum that's needed.