• Rational Numbers can be written as a ratio of one number to another.


• Integers are rational numbers with a denominator of 1.


• Fractions are rational numbers that are written with a numerator and a denominator.


• Irrational Numbers cannot be written as a ratio (e.g. pi and the square root of 2).


• Real Numbers include all the rational and irrational numbers and can be positive, negative or zero.