I completed a B.S. in Mathematics in the USA with a 3.6 major GPA.
1.) The strongest LOR I have is from a lecturer with a PhD in 2010 that I took two applied Statistics courses with. They're graduate courses for programs in Bioinformatics/Genomics etc. We covered probability theory, linear regression, multiple linear regression, nonlinear regression, ANOVA, factorial designs, split and split-split plot designs, various block designs, Hasse Diagrams etc. I know the instructor well, I performed well, and he really likes me.
2.) My one research project was in the department of biology in Bioinformatics, but I never finished the project in the deadline my PI gave me and he told me to forget about working on it more. He has refused to write me letters for scholarship applications citing his busy schedule. That would be a bad letter.
3.) I have taken three courses with a Math professor in Sets & Logic, Modern Analysis I and Modern Analysis II. I spent a lot of time in office hours speaking to him. However, my professor said that while I started strong, the thoroughness and rigorousness of my proofs declined with each class I took under him and that my letters would need to reflect that. He was hesitant. I got an A, B+ and B+ in his courses. I don't think that is a good letter.
4.) All of my other courses were just a single class with a professor I only had a course with once and didn't get to know. Of these, I got an A in undergrad probability theory, an A in undergrad Linear Algebra, and an A in undergrad Abstract Algebra. Unfortunately, for Abstract Algebra, I spent $800 on a tutor who helped me with homework / exam studying and I also occasionally sought advice to homework from the internet. I don't know how letters from these classes would look.
The only math classes I took for my Bachelor's were Sets & Logic, Linear Algebra, Abstract Algebra, Probability Theory, Modeling in Biology, Ordinary Differential Equations, Advanced Calculus 1 & 2, and Modern Analysis 1 & 2.
5.) I am currently looking for a full time job and completing an online B.S. degree (for cost) in Computer Science from a university across the state to meet prerequisites. I will take classes with a couple professors multiple times, but I do not know how LORs from an online degree would look.
Finally, I want to say that I would like to get into a great program in Computer Science to study Machine Learning and Math Theory outside of my state. I can only afford to go International (a country with tuition < $12,000 a year) or recieve funding or a TA/RA'ship at an American University that waives 100%/most of the tuition for my entire degree.
While completing my online degree and job searching / working, I am also working on personal projects (programming) and self-studying some statistics. I can reference this in my personal statement.
I almost think that to get into a great school, I need to first do a subsidized Master's internationally (or tuition free Master's in USA) in Statistics / Mathematics at whatever school I can get accepted (while working a part time job). I would do research there and build up strong letters of recommendation from the professors. I really want to avoid loans.
I would then be able to do a second masters or PhD at a better school in the field I want to specialize in. Is attending a top graduate school even feasible for someone in my position? How bad of a position have I put myself in?
I'm currently 25.