Inequalities, intervals and solving them
Show the solutions of an inequality on a number line: filled or hollow circle, segment or arrow. Then solve inequalities and see why multiplying by a negative number turns the sign round.
- UK: Year 9
- France: grade 9
- Germany: grade 7
- Iran: grade 9
- Afghanistan: grade 9
- Syria: grade 9
- Palestine: grade 9
- Ukraine: grade 9
- Russia: grade 6
Guide
This studio follows KS3 "vocabulary of inequalities" and GCSE A22: solve linear inequalities and show the solution set on a number line.
x > 3 means every number greater than 3: not just 4, 5 and 6, but 3.1 and 3.01 too. So we shade one unbroken piece of the number line.
A filled circle means the number itself is a solution (≤ or ≥). A hollow circle means it is not (< or >).
Tap the line to draw a piece. Choose its shape with the buttons: arrow to the left, segment, or arrow to the right. Drag the circles to move them, and tap a circle to make it filled or hollow.
Solve an inequality like an equation: add or subtract the same number on both sides, multiply or divide both sides by the same positive number. But if you multiply or divide by a negative number, the inequality sign turns round.
The triangle above the line is a test number: drag it and see whether the inequality is true or false there.