There are several sets of numbers, which will be discussed below.
The set of real numbers
Effect 
.
Rational and irrational numbers form the real numbers. They are numbers that can be represented in the form of infinite decimal fractions.
The set of Complex numbers
Effect 
.
It is numbers of the form 
, where 
; 
is the imaginary unit.
The set of Rational numbers
Effect 
.
Combining whole numbers with a decimal, get a rational number
Rational numbers can be represented in the form of irreducible fraction 
, where 
integer 
is a natural number written as infinite periodic decimal fractions).
The set of Irrational numbers
They are numbers that can be written in the form of an infinite non-periodic decimal fractions.
The set of integers
Effect 
.
Include natural numbers, their opposites numbers (negative) and the number 
.
The set of natural numbers
Effect 
.
They are positive integers.
Fractional numbers
It's a numbers composed of integer fractions of a unit.
— common fractions; 
— decimals 
