Sharing in a three-part ratio
Share amounts in a:b:c and check that the parts add to the total.
Key formulas
What this lesson covers
This lesson builds Secondary 2–3 skill in three-part ratio. 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 (three-part ratio) 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 — three-part ratio
Problem. Apply the method for three-part ratio with the numbers 9 and 4.
Solution. Identify the rule for three-part ratio. Substitute 9 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 / 4Warm-up on three-part ratio: what is 6+4?
Practice questions
- Practice 1 on three-part ratio: compute with the value 27.
- Practice 2 on three-part ratio: change the numbers and repeat the same method.
- Practice 3 on three-part ratio: write one sentence explaining the key rule.
- Practice 4 on three-part ratio: invent a similar exam-style question and solve it.
Study notes
What is the main idea of three-part ratio?
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.