For a little more context: I'm currently an undergrad (sophomore) at a small liberal arts college with a (from my experience so far) solid math program. So far, I've taken Calc I, II, III, linear algebra, and an introduction to the logic class. This semester I'm taking graph theory and differential equations, an intro to statistics class, and an intro to proofs class. And outside of class, I'm (very slowly) working through an abstract algebra textbook.

What are some ways I can find questions that are accessible to me as a pretty mathematically inexperienced undergraduate? I don't even mean questions that are open or unsolved, just any questions that would be accessible that I could play around with and get a taste of working through.