resources

there are SOO many great free resources out there, so here are just my top picks :D

youtube: Art of Problem Solving, Daily Challenge with Po-Shen Loh, Terry Chew Academy, Sohil Rathi, Chan Lye Lee, Chen Hongming, Math Divulged
websites: AoPS Alcumus (i grinded this sm during quarantine era lol), MathDash (essentially the cf of math), AMC Course (to train past AMC problems by topic)
books: Omega Learn Books, Math Competitions I, Math Competitions II

youtube: Michael Greenberg (this guy is literally the reason for my geom skills), Online Math Club, Shefs of Problem Solving, Calimath (check out their awesome website as well), vEnhance (Evan Chen), CNCM, Dedekind cuts, little fermat, OlympicMathTutor
books: A Beautiful Journey Through Olympiad Geometry (okay to me, there is NO book that can compare to this one and i love this book w my life hehe. there are other great books too like EGMO, MONT, Olympiad Combinatorics, etc. but none of them hits the same like this one, so this is gonna be the only book i actually recommend lol, but the ones i listed earlier are pretty good too)

math (non-oly): 3B1B (duh), Mathematical Visual Proofs, Think Twice, Numberphile, Eddie Woo (it's impossible to not love this guy), YC Mathematics, Physics and Chemistry (he's 94 but his brain is so sharp like howw-)
miscellaneous fun stuff: TED-Ed, Pursuit of Wonder, Vsauce, Big Think, exurb1a, Veritasium, Odd Animal Specimens, Crash Course, Cognito, The School of Life, The Why Files, Be Smart, Sisyphus 55

my current most orz resource is this compilation of 314 contest-style math problems
pintarian mathletes has nice materials too hehe
you can find some of my other teaching materials here (for math ofc)
aceterus for grinding spm trial papers!! (a project i worked on with jack + chin wei + amelia, instagram)