These are notes I typed up during my attempts to understand mathematical concepts. It could contain as little as a single theorem or as much as a whole subject, depending on the reason I read them. As the time progressed, I noticed I had so many notes, and I thought it might be useful for someone out there. That is why I decided to post these notes.

The first disclaimer is that these notes are initially for myself, so some tedious calculations or proofs might be included/omitted. Secondly, it certainly contains some (indeliberate) mistakes, so if you find any mistakes or have any suggestions, feel free to contact me via my email. I would be happy to update these notes.

Calculator

• Six degree of freedom calculator 

• Sudoku checker

• Desmos.com - graphing calculator

• WolframAlpha.com - Mathematica-based scientific calculator

• Pi-Base - database of topological spaces and their properties (very powerful for providing counterexamples)

Teaching Material

• Lean Game - interactive game for learning Lean

• Texnique - LaTeX practicing game

• Project Euler - Mathematical problems suitable for practicing computer programming

• Can human generate a truly random sequence of H and T?

• 100 Debates in mathematics