The ComplexNumber type exposes the following members.
Addition of Complex numbers (doesn't change this Complex number). (x+i*y) + (s+i*t) = (x+s)+i*(y+t)
Division of Complex numbers.
Multiplication of Complex numbers.
Subtraction of Complex numbers. (x-i*y) + (s-i*t) = (x-s)+i*(y-t)
Negative of this complex number (chs stands for change sign). This produces a new Complex number and doesn't change this Complex number. -(x+i*y) = -x-i*y.