factor: 1. (noun) Any of the values involved in a multiplication problem that when multiplied together produces a result. 2. (verb) To rewrite an algebraic expression as a product.

factorial: An operation that multiplies a whole number by every counting number smaller than the whole number.

FOIL: 1. An acronym for first, outer, inner, and last — which indicates the order in which two terms (one from each of two binomials) are multiplied together. 2. The process of multiplying two binomials.

formula: A rule or method that is accepted as true and used over and over in common applications.

fraction: Any quantity expressed as a numerator (the value above the fraction line) and a denominator (the value below the fraction line).

fraction line: A line separating the numerator from the denominator in a fraction.