Definitely start with Khan academy for pretty much everything up to calculus (or even including it). Then Linear algebra—as usual, I highly recommend Boyd’s tex

Definitely start with Khan academy for pretty much everything up to calculus (or even including it). Then Linear algebra—as usual, I highly recommend Boyd’s text: https://web.stanford.edu/~boyd/vmls/ https://web.stanford.edu/~boyd/vmls/ as it’s very approachable and practical, and then going on to statistics and probability. You’ll need linear algebra and probability to formalize most concepts in economic theory among many other fields, but both are incredibly practical and will be useful throughout.