Every percentage question decomposes into 10%, 5% and 1% building blocks. A child fluent in assembling 35% = 25% + 10%, or finding 1% and scaling up, solves these in seconds rather than reaching for long, error-prone written methods. Percentages sit at the heart of the 11+ maths syllabus because they pull together fractions, decimals, division and reasoning all at once, which is exactly why examiners love them. This guide teaches the core methods step by step, shows the traps that cost marks, explains how percentages appear in a real GL Assessment paper, and points you to the free graded worksheets and timed mocks on Quest Arena.
What 11+ percentages questions actually test
At 11+ level, "percentages" is really four connected skills: finding a percentage of an amount, working out a percentage increase or decrease, spotting reverse percentages, and converting fluently between fractions, decimals and percentages. Under the current GL-dominant system (GL Assessment now sets most regional 11+ papers after CEM's separate tests were phased out around 2022–2023), these appear as tightly timed multiple-choice questions with answers A–E on a separate OMR sheet, no calculator allowed. That format rewards mental shortcuts over heavy written arithmetic.
Our free worksheet library grades every sub-skill across four tiers — Foundation, Developing, Secure and Greater Depth — so a Year 4 or 5 child can enter where they are comfortable and climb toward Year 6 exam standard. The GL papers hub then puts the same skills inside full exam-style sets.
The one method that unlocks everything: find 1% and 10%
Teach your child to break any percentage into friendly parts. To find 10%, divide by 10. To find 1%, divide by 100. From those two anchors you can build almost any percentage without a calculator.
Worked example — 35% of 240:
- 10% of 240 = 24 (just move the digits: divide by 10).
- So 30% = 24 × 3 = 72.
- 5% is half of 10%, so 5% = 12.
- 35% = 30% + 5% = 72 + 12 = 84.
No long multiplication, no decimals to line up — just halving, doubling and adding. This "build-it-from-blocks" habit is the single biggest time-saver on percentage questions, and it is the approach our Foundation and Developing sheets drill first.
Percentage increase and decrease
Increase and decrease questions add one step: find the percentage part, then add it to or subtract it from the original.
Worked example — a £60 coat is reduced by 15%:
- 10% of 60 = 6, so 5% = 3, so 15% = 6 + 3 = 9.
- The coat is reduced, so subtract: 60 − 9 = £51.
For an increase, you add instead. A common exam-level shortcut for Year 6: a 15% decrease means the child pays 85% of the price, so 85% of 60 = 51 in one calculation. Teaching both routes helps, because the multiple-choice options are often designed to catch a child who adds when they should subtract.
Reverse percentages — the top mark-loser
Reverse percentages are where strong children pull ahead. Here you are told the answer after a change and must find the original. The trap is to take a percentage of the new figure instead of working back to 100%.
Worked example — after a 20% increase, a game costs £36. What was the original price?
- £36 represents 120% of the original (100% + 20%).
- Find 1%: 36 ÷ 120 = 0.30.
- Scale to 100%: 0.30 × 100 = £30.
The rule to memorise: match the money to its percentage first, find 1%, then scale to 100%. Practise this on a couple of Greater Depth sheets and it stops feeling like a trick.
Fraction, decimal and percentage conversions
Fast conversion is non-negotiable, because many GL questions hide a percentage inside a fraction or decimal comparison. Learn these common equivalences by heart so no working is needed:
| Fraction | Decimal | Percentage |
|---|---|---|
| 1/2 | 0.5 | 50% |
| 1/4 | 0.25 | 25% |
| 3/4 | 0.75 | 75% |
| 1/3 | 0.333… | 33⅓% |
| 1/5 | 0.2 | 20% |
| 2/5 | 0.4 | 40% |
| 1/10 | 0.1 | 10% |
| 1/100 | 0.01 | 1% |
The two rules behind the table: to turn a decimal into a percentage, multiply by 100 (0.35 = 35%); to turn a percentage into a fraction, write it over 100 and simplify (40% = 40/100 = 2/5). These conversions overlap heavily with our CSSE and independent-school material, where percentage-fraction links appear in longer free-response questions.
How percentages appear in a real GL 11+ paper
A typical GL maths paper runs to around 50 questions in about 50 minutes — roughly a minute per question — with answers marked A–E on a separate answer sheet and no calculator. Percentage questions usually sit in the middle-to-hard band and are frequently worded (shop discounts, test scores, populations). The raw mark is later converted to a Standard Age Score (SAS, roughly 69–141 with 100 as average, and many grammar schools looking for about 111+), and because the score is age-adjusted, younger pupils in the year group are not penalised for their birth month.
The practical takeaway: aim for around 45–55 seconds on a straightforward percentage question so you bank time for the reverse-percentage stinkers later in the paper. Our timed on-site mini-mocks and the full mock library reproduce this pressure exactly.
Common mistakes and exam traps
- Percentage of the wrong number: in reverse questions, children take a percentage of the new amount instead of working back to 100%.
- Add/subtract confusion: "reduced by" means subtract, "increased by" means add — the last line of the question decides which.
- Forgetting to simplify: a fraction answer like 40/100 must become 2/5 to match the printed option.
- Misreading the question's final sentence: a worded problem often asks for the discount, not the new price — read the last line twice.
- Decimal slips: multiplying by 100 the wrong way (moving the point in the wrong direction).
Difficulty progression: Year 5 versus Year 6
Year 5 (Foundation/Developing): "Find 25% of 80." A child halves 80 to get 40, halves again to get 20. One step, friendly numbers.
Year 6 (Secure/Greater Depth): "A jacket is reduced by 30% in a sale to £42. What was the original price?" This needs the reverse method: £42 = 70%, so 1% = 0.60, so 100% = £60. Same underlying skill, several more steps and a trap built in. Building a child from the first version to the second is exactly what the graded tiers on Quest Arena are designed to do — and you can track coverage across the whole syllabus using our free revision hub.
Frequently asked questions
Is a calculator allowed in the 11+ percentages questions?
No. GL papers are non-calculator throughout, which is why the "find 1% and 10%" mental method matters so much — it replaces long division with quick halving and doubling.
How much time should my child spend per question?
Roughly a minute, since a GL maths paper is about 50 questions in 50 minutes. Aim to finish straightforward percentage questions in under a minute to leave thinking time for reverse percentages.
Which topics should we practise alongside percentages?
Fractions, decimals and ratio — they share methods and often appear in the same question. Work through those free worksheet sets together so conversions become automatic.