Knowledge Organiser: Sharing in a Ratio
Part of Ratio Sharing · GCSE GCSE Mathematics revision
This topic summary covers Knowledge Organiser: Sharing in a Ratio within Ratio Sharing for GCSE Mathematics. Revise Ratio Sharing in Ratio & Proportion for GCSE Mathematics with 14 exam-style questions and 12 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 7 of 7 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 7 of 7
Practice
14 questions
Recall
12 flashcards
Knowledge Organiser: Sharing in a Ratio
Key Terms
- Ratio: A comparison of two or more quantities using the : notation
- Parts: The individual shares that a ratio is divided into
- Total parts: The sum of all the numbers in the ratio
- One part: The total amount divided by the total number of parts
- Unequal sharing: Dividing a quantity so each person gets a different amount based on the ratio
Must-Know Facts
- Add the ratio numbers together to find the total number of parts
- Divide the total amount by the total parts to find the value of 1 part
- Multiply 1 part by each ratio number to find each share
- Always check: your shares must add back up to the original total
- If given the difference between two shares, find how many parts the difference represents
- Ratios can have 2, 3 or more parts (e.g. 2:3:5)
- The ratio 2:3 is the same as 4:6 but NOT the same as 2:5
Key Methods
- 3-step method: add parts → find 1 part → multiply each
- Difference method: if told A gets £x more than B, find the difference in parts, then 1 part = £x ÷ difference
- Working backwards: if one share is given, divide by its ratio number to find 1 part, then multiply total parts
- Check: shares must sum to the original amount
Common Mistakes
- Using total parts as the divisor: For ratio 3:5, divide by 8 (total parts), not by 5 — add all parts of the ratio first
- Not checking shares sum to the total: Always verify your three (or two) shares add back to the original amount
- Difference method errors: If B gets £40 more than A in ratio 3:5, the difference is 5 − 3 = 2 parts = £40, so 1 part = £20 — not 1 part = £40
- Wrong number of parts for three-way ratios: For a:b:c, total parts = a + b + c — students often forget to include all three
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Practice Questions for Ratio Sharing
£300 is shared in the ratio 2:3 What is the smaller share?
Liam says: "If you share £50 in the ratio 1:4, the larger share is £40." Explain why Liam is correct.
Quick Recall Flashcards
14 questions on Ratio Sharing — practise free
Instant marking, adaptive difficulty, and 12 spaced repetition flashcards. Free until your GCSEs.
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