Answer:
Any number that can be represented as a ratio of two integers is a rational number. In other words if I had the whole number 10, it can be expressed as 10/1.
Repeating numbers can also be rational for they terminate themselves.
So, if you had the number 0.333... it can be expressed as 1/3.
An example of an irrational number is the number pi 3.14159
The same number is not repeated and therefore can not be expressed as a fraction or a ratio.