Rational number - a real number that can be written as a ratio of two integers with a non-zero denominator.
Greatest Common Factor - the greatest number that is a factor of two or more given numbers.
Least Common Multiple - the smallest number that is a common multiple of two or more given numbers.
Prime: a whole number greater than 1, whose only two whole-number factors are 1 and itself
Composite: A whole number that can be divided evenly by numbers other than 1 or itself