https://interestingengineering.com/11-of-the-best-youtube-channels-for-understanding-mathematics
Below are some of the best and Free Math channels from Secondary School to University to Public Math Enthusiasts.
1. Khan Academy (School Math, Sponsored by Bill Gates)
2. Numberphile (Math Curiosity)
3. WooTube (School Math)
4. Linear Algebra (Undergrad Math)
5. Rigourous French Math (Classe Prepa, Undergrad Math)
Set Theory Basics (Baccalaureate Math Revision)
Espace Vectorielle (French Abstract Version of Linear Algebra)
Rigorous French Math (Classe Prepa)
Singapore Maths Tuition 