Interval Notation


There are two ways to write an inequality: using a Number Line or with Bracket Notation.




Bracket Notation

Less than : <

Greater than : >

Less  than and/or equal to: ≤

Greater than and/or equal to: ≥




Excluded: ( ) – circle brackets Excluded means that if the interval is “greater than 5”, then 5 isn’t included in the range. Therefore, use circle brackets.

Included: [ ] – square brackets Included means that if the interval is “greater than or equal to 5”, then the 5 is included, therefore use square brackets.





Number Lines





If you have any questions, leave them in the comments below.