Complex sets are divided into real sets and imaginary sets.

Real number sets are divided into algebraic number sets and transcendental number sets.

Algebraic number sets are divided into rational number sets and algebraic irrational number sets.

Algebraic irrational number set plus transcendental number set is called irrational number set.

Rational number sets are divided into integer sets and decimal sets.

Integer sets are divided into positive integer sets and zero and negative integer sets.

A positive integer set plus zero is called a natural number set or a non-negative integer set.

Positive integer sets are divided into prime number sets and composite number sets.

Integer sets can also be divided into odd sets and even sets.

The above real number set and rational number set can also be classified by positive and negative.