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Seven ways to stretch the most able in the same lesson as everyone else, from Key Stage 3 through to A-Level.
Differentiating for the most able is one of the most common challenges in a mixed ability mathematics classroom. The temptation is to write a second lesson, or to park those students on an extra worksheet once they have finished. That is extra planning, and it often means the stretch arrives too late to matter.
The better move is to change the demand of the same objective. Ask for a proof instead of a calculation. Link a second topic. Reverse the problem. Replace numbers with algebra. The class still shares the starter, the modelled examples and the vocabulary. The most able are already working further on by the time you set the independent task.
The seven approaches below are the ones I come back to with KS3, GCSE and A-Level classes. None of them needs a completely separate lesson. They sit inside the packs in the proof, algebraic fractions and problem solving libraries, and they match the questioning I set out in Questioning in Mathematics Lessons.
Proof asks students to extend what they already know through precise reasoning. They stop calculating a single case and start writing a general argument, often with algebraic notation.
That is a different demand from another ten practice questions. The skill is already secure. What they lack is the habit of saying why it is always true.
The proof lesson collection and Deriving a Mathematical Proof are written for this. Students move from a numerical example to an identity, then to a written argument. That is the same step later required in circle theorems and in A-Level deduction.
One of the things I like most about mathematics is that it is continuous. Linking two topics consolidates both. It also adds depth to the objective without changing the starter.
Working the problem in reverse does the same job. The class finds an area. The most able investigate which rectangles are possible for a fixed perimeter.

This is the same idea as problem solving in secondary maths. Two facts have to be joined. The most able are not given a new topic. They are given a second topic inside the one you are already teaching.
A simple concept applied to a run of harder questions raises the pace without a new PowerPoint. Students can also use the success criteria to write questions for a partner. The person who wrote them later marks and feeds back.
The important part is that easy, medium and hard share the same objective. Hard is not a surprise topic or bigger numbers. It is the same skill with an extra constraint, a compound diagram or a reverse problem.

Every KS3 and GCSE pack on the site already sequences questions this way. You do not need a second sheet for the students who finish first. You need the next question in the same sequence.
Whether it is angle geometry, ratio or algebra, mathematics is full of patterns. Learning to look for them, and to explain where they come from, is how students reach a deeper understanding. Patterns show how topics connect and how a result can be generalised.
I ask the most able to write the pattern in words first, then in algebra. A guess that stays as a guess is not enough. They have to test it on a new case, then say whether it always holds.
This pairs well with “Is it always, sometimes or never true?” from the questioning techniques. The most able need a hypothesis to defend, not another identical calculation.
Working with degrees of accuracy asks students to think about the limits of a calculation rather than a single answer. It extends any topic that uses measurements or rounded values, because students have to consider what could have happened before the rounding took place.
Most classes will find a density, a speed or an area from exact values. The most able find the range of possible values. That is a small change to the question and a large change to the thinking.
Calculations using bounds is the Higher lesson I use for this. Once students can write an error interval, the stretch is to put those bounds inside a compound calculation, including Pythagoras and trigonometry.
Solving an equation is only half the challenge if the equation has already been given. Asking the most able to derive it first, from a diagram, a sequence or a worded situation, extends the task before a single step of algebra has been written down.
The rest of the class can still solve a prepared equation. The most able spend the extra minutes forming it. That is the part that later appears in GCSE AO3 and in A-Level modelling.
This is why I keep mixed questions inside ordinary lessons rather than saving them for revision. The problem solving library is built around forming the mathematics before calculating it.
Once students are confident adding, subtracting or simplifying fractions with numbers, the natural extension is to replace those numbers with algebraic expressions. The method stays the same. The demand of the calculation increases considerably.
This is one of the cleanest differentiations I use, because you do not need a new explanation. You change the numbers to letters and keep circulating.
The algebraic fractions collection sequences this from single-bracket KS3 work through GCSE factorising to A-Level partial fractions. The stretch is already in the later questions of the same pack.
You do not need a separate extension booklet. These collections build proof, reverse problems and algebraic generalisation into the later questions of the same lesson.
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Differentiation does not have to stop at the lesson. There are a few well established routes for stretching your most able students further, depending on their key stage.
For A-Level students, the Pearson Edexcel Advanced Extension Award is worth considering. It is sat alongside the normal A-Level course and draws on the same subject content, but the questions are far more demanding, so it rewards depth of understanding rather than extra content. A distinction is worth 40 UCAS points and a merit is worth 24.
For Higher tier GCSE students aiming at grade 7 or above, the Pearson Edexcel Level 2 Extended Mathematics Certificate gives genuine stretch. It builds on GCSE Higher content with a strong focus on algebra and algebraic manipulation, and it is designed to support the transition to A-Level. That sits alongside the GCSE Higher scheme of work for Years 9 to 11 and the grade 7 to 9 revision programme.
The UK Mathematical Challenges are also worth promoting, whichever key stage you teach. The Junior, Intermediate and Senior Challenges stretch problem solving well beyond the curriculum. The team events, such as the Team Maths Challenge, work particularly well as the basis for an after-school maths club.

Keep the same starter and the same modelled examples. Replace the last independent question with a proof, a reverse problem or an algebraic version. The most able should not be waiting for you to finish with the rest of the class.

Write the three levels from the same objective before the lesson. Hard should still be that objective. A compound shape, a negative power or an unknown data value is enough. A new topic on a photocopied sheet is not.
Once a numerical example is secure, ask whether it is always true. Then ask them to write it with algebra. Proof, bounds and algebraic fractions all come from that one move.
If the extra challenge only lives in the last ten minutes, it reaches the students who were already going to get there. Put a proof, a linked topic or a mixed question on the second visit to the skill, not only on the first teach.
More able: keep the first step hidden. Ask for a proof, a generalisation, bounds, or an equation formed from a diagram. Use the later questions in the same pack. Do not send them to a different worksheet in a different topic.
Less able: keep the same objective and reduce the arithmetic. A writing frame of I know… I need… First I will… lets them reach the method without turning the lesson into isolated drill. Stretch for the most able should not remove the core examples the rest of the class still needs.
| Approach | What students do instead | Where it sits on the site |
|---|---|---|
| Proof | Justify a general case, not a single calculation | Proof lessons; quadratic formula; recurring decimals |
| Link or reverse | Join two topics, or work the problem backwards | Problem solving library |
| Easy, medium, hard | Same objective, extra constraint | Later questions in every KS3 and GCSE pack |
| Patterns | Hypothesise, test, generalise | Questioning techniques |
| Bounds | Find a range of possible values | Calculations using bounds |
| Derive first | Form the equation from a diagram or context | Linear equations problem solving; sequences |
| Algebraic fractions | Replace numbers with expressions | Algebraic fractions lessons |
Use this when you plan tomorrow’s lesson, at any key stage.
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No. Change the demand of the same objective. Proof, a reverse problem, bounds or algebraic fractions raise the challenge without a second PowerPoint. A different worksheet in a different topic breaks the shared discussion and adds planning you do not need.
As soon as the method is secure, not in the last ten minutes. Have the later question on the slide or in the pack before they finish. Students who wait for extension have already stopped thinking.
It belongs in Key Stage 3. Deriving a perimeter formula, proving an angle fact or showing why 0.9 recurring equals 1 is KS3 work. If students only meet proof in Year 11, GCSE algebraic proof feels like a new subject rather than a habit they already have.
Keep the starter and modelled examples the same. Plan easy, medium and hard from one objective. The most able move on to hard while you circulate with the core. Less able students still need those core examples, so do not replace the teaching with an extension task for everyone.
For Higher GCSE students aiming at grade 7 or above, the Pearson Edexcel Level 2 Extended Mathematics Certificate deepens algebra alongside the GCSE course. For A-Level, the Advanced Extension Award uses the same content with much harder questions and carries UCAS points. UKMT challenges work at every key stage and suit an after-school club.
In the later questions of the same lesson pack. Start with the proof collection, algebraic fractions, calculations using bounds and the problem-solving library. You should not need a separate extension booklet if the pack is sequenced properly.
If you want to try one thing this week, take the next skill you were going to drill and replace the last question with a proof, a reverse problem or an algebraic version. Mark the reasoning, not only the final arithmetic.
Membership gives you 1000+ sequenced lessons from Key Stage 3 to A-Level, with PowerPoints, worksheets, exam-style questions and video tutorials. The stretch is already in the later questions, so you can walk in and teach.
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