An interval is a range of numbers between two specified values. It can be open, closed, or half-open depending on whether the endpoints are included.
Topic 2.7: 2.7 Linear Inequalities and Absolute Value Inequalities
interval cheat sheet for homework
A mathematical statement that shows the relationship between two expressions that are not equal.
The distance of a number from zero on the number line; denoted as $|x|$.
\text{In set theory}, it is the set containing all elements of given sets; often denoted as $A \cup B$.