| A | B |
| natural numbers | counting numbers |
| whole numbers | nonnegative integers |
| integers | whole numbers and their opposites |
| rational number | real number that can be written as the ratio of two integers |
| irrational number | a number that in decimal form is nonterminating and nonrepeating |
| real number | number that is either rational or irrational |
| counterexample | any example that proves a statement false |
| inequality | mathematical sentence that compares two expressions using an inequality symbol |
| opposite | a number that is the same distance from zero on the number line as a given number but in the opposite direction |
| absolute value | the distance a number is from zero; always positive |
| additive inverse | the opposite of a number |
| matrix | rectangular arrangement of numbers |
| element | an item in a matrix |
| multiplicative inverse | the reciprocal of a given number |
| reciprocal | a number which when multiplied by a given nonzero rational number equals one |