Home / Lessons / Equations & Inequalities

Inequalities with brackets

2026-12-09Equations & Inequalities Mr Ng

Expand inequalities carefully and flip only when multiplying by a negative.

Key formulas

\text{Flip when} \times / \div \text{by negative}

What this lesson covers

This lesson builds Secondary 2–3 skill in inequalities brackets. Read the key formulas, study the worked example, then attempt the written practice and the four-question MCQ review.

Method

Write every step. Name the rule you use (inequalities brackets) before substituting numbers. Keep units and signs visible until the final sentence.

Common mistakes

Students often rush the sign, use the wrong percentage base, or cancel terms instead of factors. Pause after each line and ask whether the step is reversible.

Exam habit

Underline the question verb (simplify, solve, factorise, find). Box the final answer and, where sensible, substitute back for a quick check.

Worked example

Worked example — inequalities brackets

Problem. Apply the method for inequalities brackets with the numbers 5 and 4.

Solution. Identify the rule for inequalities brackets. Substitute 5 and 4 carefully with signs in brackets if needed. Complete each operation on a new line. State the final answer clearly and check by reversing one step.

Review quiz

1 / 4

Warm-up on inequalities brackets: what is 5+4?

Practice questions

Practice 1 on inequalities brackets: compute with the value 47.
Practice 2 on inequalities brackets: change the numbers and repeat the same method.
Practice 3 on inequalities brackets: write one sentence explaining the key rule.
Practice 4 on inequalities brackets: invent a similar exam-style question and solve it.

Study notes

What is the main idea of inequalities brackets?

Apply the stated formula or rule with clear steps, then check by reversing or substituting.

How should I revise this topic?

Cover the worked example, redo the practice without notes, then complete the MCQ set and log any wrong options.