Real number set refers to the set of all real numbers; Represented by r;

Imaginary number set refers to the set of all imaginary numbers;

Pure imaginary number set refers to the set of all pure imaginary numbers;

2. Form: plural: the form of a+bi, where A is the real part and B is the imaginary part; When b=0, the complex number is a real number; When a=0 and b≠0, the complex number is pure imaginary;

So real numbers and imaginary numbers form complex numbers; Pure imaginary number is a special case of imaginary number;

3. Relationship: complex set = real set ∪ imaginary set;

The intersection of real set and imaginary set is an empty set;

Pure imaginary set is the proper subset of imaginary set;