What is the bottom number of a fraction called?

The bottom number of a fraction is called the denominator. This term is fundamental in understanding fractions, as it indicates how many equal parts the whole is divided into. For instance, in the fraction 3/4, the number 4 serves as the denominator, meaning the whole is divided into four equal parts. The numerator, which is the top number of the fraction, shows how many of those parts are considered. When interpreting fractions, identifying the denominator is crucial for understanding ratios, proportions, and various applications in real estate appraisal calculations, where divisions and comparisons are often necessary.

The other terms provided—improper and proper—are classifications of fractions but do not refer to the specific components of a fraction itself. Proper fractions have a numerator smaller than the denominator, while improper fractions have a numerator that is equal to or larger than the denominator. Thus, while these terms describe certain types of fractions, they do not define the bottom part of a fraction, which is exclusively the role of the denominator.