Definition: rational numbers are numbers that could be expressed as a ratio of two integers. For example its a decimal that keeps repeating the numbers 0.555555555 (it'll keep on going.) And that's called a irrational number.
Definition: irrational numbers are numbers that keep repeating.√2, √3, √5, √11, √21, π(Pi) are all irrational. A irrational number is a real number that can't be simplified as a fraction. But 0 will always be a rational number. Anything with "π" will always be a irrational number.
