Interval notation is a notation used to denote all of the numbers between a given set of numbers an interval. X a x b is the set-builder notation. We can use set-builder notation.
A x b is the inequality description.
Example - Using our sets from above Example. Interval notation is a way to describe continuous sets of real numbers by the numbers that bound them. A x b is the inequality description. The number 5 is included in the set so the bubble at 5 is A square bracket is never used for f f.