Hacker News
- Elementary Calculus: An Infinitesimal Approach (2000) https://people.math.wisc.edu/~keisler/calc.html 80 comments
- Walter Bradley Center Fellow Discovers Longstanding Flaw in Elementary Calculus https://mindmatters.ai/2019/04/walter-bradley-center-fellow-discovers-longstanding-flaw-in-elementary-calculus/ 6 comments
- "An elementary treatise on quaternions" - a 19th c. textbook on quaternion linear algebra and calculus https://archive.org/details/117770257 3 comments math
- Who is responsible for what we know as Newton and Leibniz's elementary calculus (as opposed to Riemann and Cauchy's real analysis)? https://www.reddit.com/r/math/comments/4xagq7/who_is_responsible_for_what_we_know_as_newton_and/ 16 comments math
- Non-Newtonian Calculus: An elementary (incomplete) introduction http://math2.org/math/paper/contents.htm 24 comments math
- Elementary Calculus: An Approach Using Infinitesimals http://www.math.wisc.edu/~keisler/calc.html 8 comments reddit.com
- This guy has made 1600+ educational videos about everything from elementary math to calculus to chemistry to banking. Oh, and they're all free. http://www.khanacademy.org 28 comments reddit.com