Here are a few comments about graduate education in mathematics. These comments are mostly NOT directed at students planning careers in K-12 education.
1. If you hope to find a job in which you use expertise in mathematics, you are very likely to need a graduate degree.
2. You should speak ASAP to a knowledgeable person about your goals, plans, and constraints. There are many options for graduate study in mathematics, but focused and detailed information is hard to find in writing.
3. If you are worried about financing a graduate program in mathematics (and who isn't), you should seriously consider applying to a PhD program. There is a lot of financial support for PhD students, usually through teaching assistantships. Usually, a teaching assistant makes enough money to support themselves (modestly) without borrowing. Support for Masters students is much more limited. Schools do not ask you for the money back if you leave after obtaining a Masters degree.
4. In addition to graduate programs in mathematics, consider programs in computer science, operations research, or statistics.
5. For students thinking about a PhD in mathematics, I recommend the book A Mathematicians Survival Guide, by Steven Krantz. You can find the book, with reviews, on Amazon.
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