What is a real number that can be expressed as a fraction called?

A real number that can be expressed as a fraction is referred to as a rational number. This is because rational numbers are defined as those numbers that can be written in the form of a fraction ( \frac{a}{b} ), where ( a ) and ( b ) are integers, and ( b ) is not zero. This includes all integers, whole numbers, and finite or repeating decimals as special cases.

In contrast, whole numbers encompass all non-negative integers, including zero, but do not include fractions. The term "irrational number" describes numbers that cannot be expressed as a fraction, such as (\sqrt{2}) or (\pi), which have non-repeating, non-terminating decimal expansions. Lastly, integers are whole numbers that can be positive, negative, or zero, but again do not include fractions. Therefore, the classification of a number as a rational number accurately captures those that can indeed be represented as fractions.