Algebra 1 · Inequalities
Open Circle
Algebra 1 · Inequalities
Definition
An open circle is a hollow dot on a number line showing the boundary value is not part of the solution.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- x > 4 uses an open circle at 4.
- x < −1 uses an open circle at −1.
Key rule
Use an open circle for < and >.
Memory hook
Open circle = excluded; the value is left out.