Inequalities — O/L Mathematics

What must I remember about Inequalities?

• Inequality Symbols: Greater than (>), Less than (<), Greater than or equal to (≥), Less than or equal to (≤).
• Properties of Inequalities: Adding or subtracting any real number on both sides preserves inequality direction; Multiplying or dividing by a POSITIVE number preserves inequality direction.
• Reversal on Negative Multiplication/Division: Multiplying or dividing both sides by a NEGATIVE number STRICTLY REVERSES the inequality sign (e.g., -2x < 6 => x > -3).
• Representation on Number Line: Open circle (○) indicates strict inequality (<, >); Solid dot (●) indicates inclusive inequality (≤, ≥).

Test yourself (1 minute)

1. Negative sign reversal trap

   Forgetting to reverse inequality sign when dividing by negative coefficient is the single most common mark-losing trap.

2. Integral Solutions

   Pay close attention to domain restrictions: 'positive integers' (x ∈ {1, 2, 3, ...}), 'whole numbers' (x ∈ {0, 1, 2, ...}), or 'integers' (x ∈ {..., -1, 0, 1, ...}).

3. Compound Inequalities

   For a < bx + c ≤ d, solve the two simultaneous inequalities independently or apply inverse operations simultaneously across all three parts.

Practise Inequalities questions today

Source: NIE G.C.E. (O/L) Mathematics Syllabus (Grade 11, Unit 20)

What should I study first?

What comes next?

Next in the syllabus

Where does Inequalities fit in the syllabus?

Grade 11 · Term 3