You don't mind knowing more, do you? Mathematics for the curious

Elementary:
1. How did Arithmetic come about and when did it become Number Theory?
2. Geometry in Geogebra with simple programs in JavaScript
3. Probabilities in real world and why both yours and AI reasoning is mostly probabilistic.
4. What is change and how to measure it?
Intermediate:
5. From linear equations to linear (and affine) spaces
6. But where do I need this linear space in a non-linear world or calculus seen from the
other side