Denominator

The denominator is the name of one of the two terms of a common fraction. It is the part of the fraction that indicates the number of fractional parts in the whole, or set. The figure below shows the various parts of a fraction.

The fraction above means that there are 12 parts in the whole, represented by the denominator. The 1 in the numerator indicates that we only have 1 part of whatever is being counted out of a total of 12 possible parts. If we had all 12 parts, we would have 1 whole, represented by either the number 1 or the fraction 12/12. In the figure below, the denominator is depicted by the total number of squares outlined in green. The number of purple square tells us the numerator of the fraction.

Fractions and ratios are closely related. Both can be used to represent parts of a whole. In a ratio, the denominator is the second term, while the numerator is the first term. The fraction, 1/12, can therefore be written in the form of a ratio as 1:12.