When you have a rational number if you can write it as the ratio of two integers:
As an example we can have the number:

that can be writen as:

The irrational numbers are those numbers that cannot be writen as the ratio of two intergers:
Tip: Irrational numbers are normally written in three ways: as a root (like the square root), using a special symbol (like pi), or as a non-repeating or ending decimal.
An example of an irrational numbers is:
3π
![\sqrt[]{2}](https://img.qammunity.org/2023/formulas/mathematics/college/wm766s3ozqpb37elhqqocwn9jzwt882ebh.png)