Ratio questions are some of the most consistently misread on the 11+ — children rush them when the structure is actually quite friendly. Once your child sees a ratio as a set of equal parts to be counted and shared, the panic disappears and a whole family of questions becomes routine marks. This guide walks through every ratio and proportion skill the current GL-dominant 11+ tests, with worked examples you can coach from even if maths was never your favourite subject.
What a ratio really means
A ratio compares quantities in fixed groups. A 2:3 ratio means two of these for every three of those. For every group of 5 (that is 2 + 3), two are one kind and three are the other. The colon is just shorthand for "for every". This matters because almost every ratio question in the exam hinges on one idea: find the total number of parts, then work out what a single part is worth.
Since 2022–2023, when CEM discontinued its separate 11+ tests and most regions moved to GL Assessment or bespoke papers, ratio has stayed a reliable topic across GL, CSSE (Essex) and independent-school papers. In a GL paper it appears as multiple-choice, with the five answers labelled A to E on a separate answer sheet, so a child who does the working correctly but mis-copies the number still loses the mark. Neatness counts. You can build that habit with our free worksheets and timed mock papers.
The "find the part" method for sharing
This is the single most important ratio skill. Take "Share £30 in the ratio 2:3." Follow three steps every time:
- Add the parts: 2 + 3 = 5 total parts.
- Find one part: £30 ÷ 5 = £6 per part.
- Multiply back: first share = 2 × £6 = £12; second share = 3 × £6 = £18.
Always check your two answers add back to the original total (£12 + £18 = £30). If they do not, something has gone wrong — that thirty-second check catches most careless errors. This works for three-way shares too: "Share 48 sweets in the ratio 1:2:3" gives 6 parts, so one part is 8, and the shares are 8, 16 and 24.
Sharing an amount unequally — worked in full
"Amara and Ben share £72 in the ratio 5:3. How much more does Amara get than Ben?" Total parts = 5 + 3 = 8. One part = £72 ÷ 8 = £9. Amara gets 5 × £9 = £45; Ben gets 3 × £9 = £27. The question asks for the difference, not either share, so the answer is £45 − £27 = £18. Read the last line twice: exam writers love to switch the question at the end.
Proportion: always go via one unit
Proportion questions scale a recipe or a rate up or down. "5 oranges make 400ml of juice; how much do 8 oranges make?" Work out the value of one orange first: 400 ÷ 5 = 80ml. Then multiply by the new number: 80 × 8 = 640ml. Going via the single unit works every time and stops children guessing.
Recipes are the classic dressing for this. "A recipe for 4 people uses 200g flour and 3 eggs. How much for 6 people?" Find the per-person amount (50g flour, 0.75 eggs) or, more elegantly, scale by the ratio 6:4 = 3:2, so multiply each ingredient by 3 then divide by 2: flour = 200 × 3 ÷ 2 = 300g; eggs = 3 × 3 ÷ 2 = 4.5. Both routes give the same answer.
Direct versus inverse proportion
Most 11+ proportion is direct: more oranges, more juice. Occasionally, especially in independent and CSSE papers, you meet inverse proportion, where more of one thing means less of another. "3 painters take 8 hours; how long for 4 painters?" Total work is fixed at 3 × 8 = 24 painter-hours, so 4 painters take 24 ÷ 4 = 6 hours. The clue is that the answer should go down as the number goes up.
Simplifying and equivalent ratios
Ratios simplify exactly like fractions: divide both (or all) sides by their highest common factor. 12:18 divides by 6 to give 2:3. Equivalent ratios also let you fill in a missing value. "The ratio of cats to dogs is 3:4. There are 15 cats. How many dogs?" The scale factor from 3 to 15 is ×5, so dogs = 4 × 5 = 20. Keep the sides in the same order you were given, or a correct calculation becomes a wrong answer.
Quick reference: ratio question types
| Question type | Key step | Worked mini-example |
|---|---|---|
| Share a total | Total ÷ sum of parts = one part | £40 in 3:5 → 40÷8=5 → 15 and 25 |
| Find one share from another | Match parts to the known amount | Ben's 3 parts = £27 → 1 part £9 |
| Difference between shares | Subtract the two shares | 45 − 27 = 18 |
| Scale a recipe (direct) | Find per-unit, then multiply | 400ml ÷ 5 × 8 = 640ml |
| Inverse proportion | Multiply to a fixed total, then divide | 3×8 ÷ 4 = 6 hours |
| Simplify / equivalent | Divide by the HCF; keep order | 12:18 = 2:3 |
Exam traps that cost real marks
Ratio is generous with marks and generous with pitfalls. Warn your child about these:
- Forgetting to add the parts. Dividing £30 by 2 or by 3 instead of by 5 is the number-one error.
- Answering the wrong share. The question may ask for the smaller share, the larger, or the difference — underline what is wanted.
- Not simplifying the final ratio. If the answer options are simplified, 4:6 will not appear; the mark is on 2:3.
- Reversing the order. "Cats to dogs 3:4" is not the same as "dogs to cats".
- Mis-copying to the OMR sheet. In a GL paper the answer letter must match the working — a fast child can still fumble the transfer.
A difficulty progression: Year 4 to Year 6
Build ratio confidence in stages. A Year 4 or 5 starting point is a clean two-way share of a small, easily divisible number: share 20 in 1:3. A Year 6 exam-level version adds a twist — three-way shares, a difference at the end, a non-obvious total, or a proportion wrapped in a word problem. The underlying method never changes; only the reading demands grow. Pair each new type with a target of about a minute per question, mirroring the GL pace of roughly 50 questions in 50 minutes, and track your child's coverage against our revision hub.
A tidy mental shortcut: when you find "one part", write it in the margin and circle it. Every remaining step is just that number times a whole number, which children can often do in their head, saving precious seconds. For more of these, see our companion guide on GL paper formats and the wider exam guides.
Frequently asked questions
Is a calculator allowed for ratio questions?
No. GL 11+ maths is a non-calculator paper, so ratio arithmetic has to be done by hand or mentally. That is exactly why the "find one part" method matters — it keeps every step to simple multiplication and division a child can do quickly and accurately.
How often does ratio come up in the exam?
Ratio and proportion are core topics and appear on almost every paper, usually as two or three questions ranging from a straightforward share to a multi-step word problem. Because the method is so repeatable, it is one of the best-value topics to master — a small amount of practice reliably converts into marks.
Does my child need ratio for GL, CSSE and independent schools?
Yes. Ratio is common to all three, though the dressing differs: GL keeps it multiple-choice and tightly timed, while CSSE (Essex) and independent papers may ask for written working and sometimes fold in inverse proportion. The CSSE papers and centre-specific mocks let your child practise the exact style their target school uses.