A rational number can be written as a fraction and as a ratio. Every whole number is a rational number, because any whole number can be written as a fraction. It doesn't have any endless non-repeating digits.
Examples of rational numbers:
An irrational number is a number that are not rational and can be written as a decimal, but not as a fraction. It has an endless non-repeating digits to the right of the decimal point.
Examples or irrational numbers:
Pi = 3.141592...