# Decimal numbers and fractions

A decimal number is any real number that consists of an integer part and a decimal part, which are separated by a comma. In other words, a decimal number is a real number that we recognize by carrying a comma and can be divided between an integer part and a decimal part.

## Fraction

A fraction is expressed in the form:

Both the numerator and denominator can be numbers or functions. If they were functions that depend on the same variable, we could write it as follows:

## Decimal number

A decimal number is expressed in the form:

Where e is a whole number and all the following letters d stand for decimal. Therefore, in a decimal number we will always find an integer part. The integer part is the number before the comma. The decimal part is the part after the comma.

### Scheme of the structure of a decimal number

The decimal part is also called the fractional part . So, knowing that it receives this name, we can already think that decimal numbers and fractions share things.

## Decimal numbers and fractions

What do decimal numbers and fractions have in common?

Decimal numbers and fractions have so much in common that they become the same mathematical concept but with a different expression. In other words, decimal numbers and fractions are the same but written differently:

## Let’s prove it

We suppose that we want to write the number 4.5 as a fraction.

First we have to think of two numbers that divided into 4.5. This combination of numbers can be any number. For example, 9 and 2

Any equivalent function will result in 4.5.

We obtain 4.5 by dividing 9 by 2, such that: