In mathematics, an interval is a set of real numbers that includes all numbers between two endpoints. Writing these requires specific brackets to indicate whether those endpoints are included in the set: Closed Interval
Used when a set continues forever in one or both directions, such as for all real numbers. 2. Music: Pitch Distance interval
: Excludes both endpoints. On a number line, these are marked with . Half-Open Interval : Includes one endpoint while excluding the other. In mathematics, an interval is a set of