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