The golden number Φ

Mathematical induction

Ptolemy's theorem

Napoleon's theorem

Straight lines

Conics

The real transcendental functions

Geometric vectors

Complex numbers

Spherical trigonometry  Spherical zones and spherical caps

Mathematica with WolframAlpha

Vector spaces and linear operators

Integrals 
Partitions 
Prime numbers 
Probability 
Euclid's Algorithm 
Collatz's conjecture

Continued fractions

Egyptian fractions

Pythagorean triples

The Mandelbrot set
