- Complex numbers and their geometric representation in the plane.
- Phylogeny of the concept of a complex number.
- Transformation of ortonormal coordinates into complex coordinates in the plane (and vice versa).
- Distance between two points in complex coordinates.
- Analytic description of a line and a circle in complex coordinates.
- Congruence.
- Residue classes.
- Fermat and Euler theorem.
Complex numbers, operations with c.n., relations of the operations with geometric mappings in the plane. n-th root of a c.n., polygons. Applications.
Residue classes, Fermat and Euler theorem.