First Khan Academy, then if you want to go further: Bill Shillito | Introduction to Higher Mathematics (YouTube lecture course) - https://www.youtube.com/playl

First Khan Academy, then if you want to go further: Bill Shillito | Introduction to Higher Mathematics (YouTube lecture course) - https://www.youtube.com/playlist?list=PLZzHxk_TPOStgPtqRZ6KzmkUQBQ8TSWVX https://www.youtube.com/playlist?list=PLZzHxk_TPOStgPtqRZ6Kz... Richard Hammack | Book of Proof (pdf book) - https://www.people.vcu.edu/~rhammack/BookOfProof/ https://www.people.vcu.edu/~rhammack/BookOfProof/ Taylor Dupuy | Fundamentals of Mathematics (YouTube lecture course) - https://www.youtube.com/playlist?list=PLJmfLfPx1OedcIUn5nSCZQEtJrhLusB5Y https://www.youtube.com/playlist?list=PLJmfLfPx1OedcIUn5nSCZ... Silvanus P Thompson | Calculus Made Easy (html book) - https://calculusmadeeasy.org/ https://calculusmadeeasy.org/ (This shouldn't be your only exposure to Calculus. It is more for building intuition.) Dana Mosely | Understanding Basic Statistics (YouTube lecture course, no calculus) - https://www.youtube.com/playlist?list=PL9Wxhr5qVFN0WY2CXB4tRfkpst3io7zXJ https://www.youtube.com/playlist?list=PL9Wxhr5qVFN0WY2CXB4tR... Gilbert Strang | Highlights of Calculus (YouTube lecture course) - https://www.youtube.com/playlist?list=PLBE9407EA64E2C318 https://www.youtube.com/playlist?list=PLBE9407EA64E2C318 Josh Starmer | StatQuest (Short various statistics videos) - https://www.youtube.com/c/joshstarmer/playlists https://www.youtube.com/c/joshstarmer/playlists Bob Franzosa | Introduction to Topology (single public lecture) - https://www.youtube.com/watch?v=zsN_guq__Ac https://www.youtube.com/watch?v=zsN_guq__Ac Socratica | Abstract Algebra (short videos) - https://www.youtube.com/playlist?list=PLi01XoE8jYoi3SgnnGorR_XOW3IcK-TP6 https://www.youtube.com/playlist?list=PLi01XoE8jYoi3SgnnGorR... MIT Calculus Revisited (Single Variable Calculus): https://www.youtube.com/playlist?list=PL3B08AE665AB9002A https://www.youtube.com/playlist?list=PL3B08AE665AB9002A MIT Calculus Revisited (Multivariable Calculus): https://www.youtube.com/playlist?list=PL1C22D4DED943EF7B https://www.youtube.com/playlist?list=PL1C22D4DED943EF7B MIT Calculus Revisited (Complex Variables, Differential Equations, Linear Algebra): https://www.youtube.com/playlist?list=PLD971E94905A70448 https://www.youtube.com/playlist?list=PLD971E94905A70448 Matthew Macauley | Visual Group Theory, Differential Equations, Discrete Mathematical Structures, Advanced Linear Algebra, and Advanced Engineering Mathematics (YouTube lecture courses) - https://www.youtube.com/channel/UCH1cV4RtgI_N97M8jepiUzw/playlists https://www.youtube.com/channel/UCH1cV4RtgI_N97M8jepiUzw/pla... The Discrete Mathematics course above is probably the most important for your work. In fact I would look for more Discrete Mathematics courses if I were you as it is far more important than anything else here. Open University (BBC) | Geometric Topology (YouTube lecture course) - https://www.youtube.com/playlist?list=PLKB3Q5Oyy_RNBrS3V2WbOLjxNRkXoP5oe https://www.youtube.com/playlist?list=PLKB3Q5Oyy_RNBrS3V2WbO... Joel David Hamkins | Philosophy of Mathematics (YouTube lecture course) - https://www.youtube.com/playlist?list=PLg5tKDNI_a86OO6J9HuIngyROBsUqcf_z https://www.youtube.com/playlist?list=PLg5tKDNI_a86OO6J9HuIn... Marco Taboga | Probability and Statistics & Matrix Algebra (html book, need calculus) - https://www.statlect.com/ https://www.statlect.com/ On YouTube you can literally watch a good lecture course for just about any typical undergraduate course. You just need to know where to look. Also there are even some really good master's degree courses out there. Of course the only way to really learn the mathematics deeply is to "learn by doing", aka problems and proofs. Other than the usual big American universities another good source from India is NPTEL (https://nptel.ac.in/course.html https://nptel.ac.in/course.html). For somewhat more entertaining short lectures try: Grant Sanderson | 3Blue1Brown - https://www.youtube.com/c/3blue1brown https://www.youtube.com/c/3blue1brown Brady Haran | Numberphile - https://www.youtube.com/c/numberphile/ https://www.youtube.com/c/numberphile/ Tai-Danae Bradley, Gabe Perez-Giz, and Kelsey Houston-Edwards | PBS Infinite Series - https://www.youtube.com/c/pbsinfiniteseries/ https://www.youtube.com/c/pbsinfiniteseries/ Raymond Flood (YouTube public lectures at Gresham College) | History of Mathematics - https://www.youtube.com/playlist?list=PL_jwwOG0kPgPPiX0pcbzLFI1dLTfZnPgJ https://www.youtube.com/playlist?list=PL_jwwOG0kPgPPiX0pcbzL... There are a ton of channels starting to pop up like Grant's 3B1B (I find like a new one every week). He had a contest recently so maybe look at some of the winners. Lastly this is pretty useful if you get into higher mathematics: Math Vault | The Definitive Glossary of Higher Mathematical Jargon - https://mathvault.ca/math-glossary/ https://mathvault.ca/math-glossary/