Concrete Mathematics by Knuth
Susanne Epp Discrete Math
http://immersivemath.com/ila/index.html
https://www.youtube.com/watch?v=v818mV6jgBQ&list=PLDDGPdw7e6Ag1EIznZ-m-qXu4XX3A0cIz&index=5
https://www.youtube.com/watch?v=DBugSTeX1zw&list=PLDDGPdw7e6Aj0amDsYInT_8p6xTSTGEi2
https://www.youtube.com/playlist?list=PLHXZ9OQGMqxersk8fUxiUMSIx0DBqsKZS
http://discrete.openmathbooks.org/dmoi3.html
https://www.math.wichita.edu/~hammond/math321/discrete-class-notes.html
MIT 6.042
https://github.com/frevib/mit-cs-math-6042-fall-2010-problems
CMU
http://www.math.cmu.edu/~jmackey/151_128/bws_book.pdf
Calculus
https://ocw.mit.edu/courses/mathematics/18-01sc-single-variable-calculus-fall-2010/index.htm
Multivariable Calculus
https://ocw.mit.edu/courses/mathematics/18-02sc-multivariable-calculus-fall-2010/
Linear Algebra
https://ocw.mit.edu/courses/mathematics/18-06sc-linear-algebra-fall-2011/