The document discusses real numbers and their classification. It defines real numbers as any number that can be found on the number line, including rational and irrational numbers. Rational numbers are those that can be written as fractions, with decimal forms that terminate or repeat. Irrational numbers cannot be written as fractions and have non-terminating, non-repeating decimal forms. Examples of rational numbers given include integers and fractions, while examples of irrational numbers include π and square roots of non-perfect squares. The document provides examples of classifying numbers as rational or irrational and ordering them on the number line.