Which term is used to express proportions of a whole in mathematics?

Fractions are indeed the term used to express proportions of a whole in mathematics. They represent a part of a whole by using two numbers: the numerator and the denominator. The numerator indicates how many parts are considered, while the denominator indicates how many equal parts the whole is divided into. For instance, if a pizza is divided into 8 equal slices and you have 3 slices, you can express this as the fraction 3/8, which clearly shows the relationship between the part and the whole.

Percentages, while also representing a type of proportion, are specifically fractions out of 100. This means they convert fractions into a different format for easier understanding but are not the primary term used to describe a general proportion of a whole. Ratios express the relationship between two quantities and do not necessarily represent a proportion of a single whole; they compare two different quantities instead. Decimals are yet another way to represent fractions and can express proportions, but they are not the general term used for all such expressions. Thus, fractions are the most direct and fundamental term when discussing proportions of a whole.