| domain | The set of all possible input values for the variable in a function. |
| excluded value | A value for the variable that is not included in the domain because it would cause the function to be undefined. |
| least common denominator | The smallest number (or expression) that is a multiple of all the denominators in a group of fractions (or rational expressions). |
| least common multiple | The smallest number (or expression) that is a multiple of a set of two or more numbers (or expressions). |
| prime factorization | The process of breaking down a number (or expression) into its prime multiplicative factors. For example, the prime factorization of 12xy is 2 • 2 • 3 • x • y. |
| rational expression | A fraction that contains a polynomial as the numerator, denominator, or both. |