A worked example

This is what you actually get, on a real account.

Most of what you pay for is built from your own marked answers — so a new account has nothing to show you, and nor does a screenshot. Here is a whole one instead: eighteen questions marked, seven weeks, one topic quietly costing her the grade.

This is an example account. Every figure below belongs to a student we made up, marked against the real Cambridge 9709 syllabus. Nothing here is your data.

What it costs

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5 questions a month, marked in full — the ink, the reason for every mark, and all the course notes.
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$19.99/month
120 a month, plus the rewrite, the mastery map, your trajectory, the drills and the whole of every lesson.
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$35/month
250 a month, every subject you take, priority marking and the Sunday examiner email.
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Your first mark is free and needs no account. Cancel whenever — anything you marked stays in your account either way.

The account you are looking at

Aisha — Cambridge 9709 Mathematics

Targeting an A. Paper 1 · Oct/Nov 2026, in 54 days.

Scripts marked: 18
Marks earned: 87
Weeks active: 7

38 topics on the 9709 syllabus

1Exam ready
2Proficient
2Needs work
2Too few tries
31Not started

The mark

Every answer comes back with the examiner’s reasoning on it

This part is free and stays free. It is the bit that makes everything else worth having.

9709/12 · May/June 2023 · Q7

80%

Strong

80% · predicted A*

VERDICT

What the examiner saw

Confident, well-organised differentiation — the algebra is clean and every coordinate is right. You lost the final mark for asserting the nature of each stationary point instead of proving it. This is the single most common way marks leak on this question type: the examiner is paying for the justification, not the conclusion.

THE MARK GAP

4/5

1 mark one line away

You knew these — you just didn't write them down.

B1not awarded

You stated the nature of each point correctly, but stated it without justification. This mark needs the reasoning shown — either evaluate the second derivative (d²y/dx² = 6x − 12, giving −6 at $x = 1$ and +6 at $x = 3$ ) or show a sign change of dy/dx either side of each point. An unsupported assertion earns nothing here even when the conclusion is right.

Add

The three lines from d²y/dx² = 6x − 12 onwards are the whole difference. Your conclusion was already right — the examiner is paying for the justification, not the answer.

Show on my script

Fix this and this becomes 5 / 5.

REWRITTEN TO FULL MARKS

Your answer, taken to full marks

Your own answer, rewritten to show exactly what earns every mark.

dy/dx = 3x² − 12x + 9

3x² − $12x + 9 = 0$ x² − $4x + 3 = 0$ (x − 1) $(x − 3) = 0$ $x = 1$ or $x = 3$

When $x = 1$ , $y = 1$ − 6 + 9 + 1 = 5 When $x = 3$ , $y = 27$ − 54 + 27 + 1 = 1 Stationary points are (1, 5) and (3, 1).

d²y/dx² = 6x − 12

At x = 1: d²y/dx² = 6(1) − 12 = −6 < 0, so (1, 5) is a maximum. At x = 3: d²y/dx² = 6(3) − 12 = +6 > 0, so (3, 1) is a minimum.

WHAT EACH CHANGE EARNS

B1
The three lines from d²y/dx² = 6x − 12 onwards are the whole difference. Your conclusion was already right — the examiner is paying for the justification, not the answer.
Method
Evaluating the second derivative at each x-value separately and stating the sign is what turns an assertion into a proof. A sign-change argument on dy/dx either side of each point would earn the same mark.
Kept
Everything above the rule is unchanged from your script. Four of the five marks were already yours.

See mark-by-mark evidencescript, audit, scheme

4 / 5

Sample script, with Examiner's Inktap a line

dy/dx = 3x^2 - 12x + 9

M1 ✓

$(x - 1)(x - 3) = 0$

M1 ✓

$x = 1$ or $x = 3$

A1 ✓

So stationary points are (1, 5) and (3, 1)

A1 ✓

(1, 5) is a maximum and (3, 1) is a minimum

B1 ✗

Correct conclusion, no justification shown

TAP ANY LINE — THE AUDIT AND SCHEME CITATION FOLLOW IT

MARK AUDIT9709/12

TOTAL 4 / 5running estimate: grade A*

Examiner's note — B1

Correct conclusion, no justification shown

More about this marktopics, notes, extras

Cambridge 9709/12 (Mathematics) · Question 7 · May/June 2023

Question details

96s to mark

Marks available: 5
Your score: 4 / 5 · Grade A*
Marking style: Point-based marks
Mark points: 4 earned · 1 missed
Scheme: Official Cambridge

QUESTION

The curve C has equation $y = x$ ³ − 6x² + $9x + 1$ . Find the coordinates of the stationary points of C and determine the nature of each. [5]

Exactly the same on a free account — the ink, the reason for every mark, and the note on the one that got away. The only thing free misses here is the rewrite at the bottom.

The map

Your answers turn into a picture of what you actually know

Each one gets tagged to the syllabus, so the map fills itself in. It waits for three tries on a topic before calling it — one bad morning is not a weakness.

Syllabus coverage

Cambridge 9709 Mathematics syllabus mastered

3 of 38 leaves at Proficient or Exam Ready

Exam Ready

Proficient

Sampled

Critical

Unattempted

0%50%100%

Mastery matrix

Topic-by-topic strength

Each topic is scored independently. Tap any square for attempt history.

P1Pure Mathematics 1

P2Pure Mathematics 2

P3Pure Mathematics 3

P4Mechanics

P5Probability & Statistics 1

P6Probability & Statistics 2

Empty on a free account, because there is nothing to put in it until you have marked something. That is the real reason it is paid, not a rule we invented.

The gap

Tracking a B. Wants A. 5 points in between.

Your recent scores against real grade boundaries. It is not flattering on purpose — the two dips are the topics costing her the grade.

Grade trajectory

Your last 10 attempts

Percentages charted against Cambridge 9709 grade boundaries.

Grade estimate

Current trajectory

B95% confidence

66% rolling average across your last attempts

Target A · +5% to go

Path to next grade

Converting Differential equations (3.8) to Exam Ready will shift your projection to A.

Confidence95%

Free shows the score on each question. It cannot draw a line, because a line needs a history.

The route

Then it tells you which question to do next, and why

The map finds the weakest topic. The drill turns it into one specific thing to do this afternoon.

Your weakest spot

Drill this next

Differential equationsIB practice

You are converting 33% of the marks available on this topic across 3 attempts — the lowest on your map, and the one standing between you and an A.

Drill this

That button opens the real marking page for Differential equations. Try it now — your first mark is free and needs no account.

Free tells you how each answer went. It does not pick the next question for you or say why that one.

The question desk

It keeps a paper waiting for you, built from your weak topics

Not a browsable index — a queue. These four came up because Differential equations and Complex numbers are the two topics on her map marked “Needs work”, and each one opens straight into marking.

Cambridge International A Level

Pure Mathematics 3

9709/32Oct/Nov 20261 hour 50 minutes

Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question.29 marks

(a)
Show that the substitution u = y/x transforms the equation x·dy/dx = y + x·tan(y/x) into an equation in which the variables u and x may be separated.[3]
(b)
Hence solve the equation, given that y = ¼π when x = 1, expressing your answer in the form y = f(x).[6]
Differential equations — Separating the variables is the step you have dropped in all three attempts.
The rate at which a chemical dissolves is proportional to the mass m grams still undissolved. Initially 60 g are present, and after 20 minutes 45 g remain undissolved. Find the time taken for the mass remaining to fall to 15 g, giving your answer to the nearest minute.[7]
Differential equations — Two of your three attempts stopped at the implicit form without solving for the variable.
(a)
On a single Argand diagram, sketch the locus of points representing complex numbers z satisfying |z − 2 + i| = 2.[3]
(b)
Determine the greatest and least values of |z| for points on this locus, giving each answer in exact form.[4]
Complex numbers — Loci questions are where this topic keeps costing you marks — you read the modulus as a distance from the origin.
The complex number w is such that w³ = −8i. Find the three possible values of w, giving each in the form r(cos θ + i sin θ) where r > 0 and −π < θ ≤ π.[6]
Complex numbers — You have not attempted a roots-of-unity question yet, and it is on every recent paper.

Free can search the past papers and mark 5 questions a month. What it does not do is keep a queue for you, or pick the questions from what you keep getting wrong.

The lessons

And the courses have a half you have probably never seen

Every lesson is free to read — notes, worked examples and the live diagram. The part that makes it stick is the recall half. These are the real cards from “The nature of the economic problem”.

2281 Economics16 min · 20 sections · 8 cards

Tap a card to turn it over — this is the real thing, not a picture of it.

Read the whole lesson free →

Free gets the whole lesson to read, plus the interactive diagram and the quick check. Flashcards, the concept map and the practice questions need a plan.

The weekly email

Every Sunday it writes to you, whether you showed up or not

One email a week: what moved, what did not, and the topic still sitting where it was.

MarkSchemeSunday · 08:00

Aisha, you closed 27 marks this week

4scripts marked

74%average▲ 16 pts

54days to Paper 1

Differential equations is still the topic holding the grade back — you are converting 33% of the marks available on it. It has not moved since last Sunday.

You are 5 percentage points from your target A. Three questions on the topic above is the shortest route there.

Open this week’s drill →

On Max only — not on Free or Scholar. It compares this week against last week, so there has to be a few weeks of marking behind it before it says anything useful.

What Max adds

And if you are marking across four subjects, there is a tier above

Scholar is the one most students want. Max is for the year you are sitting everything at once.

Every subject you take, not one
Scholar builds the desk for a single focus subject. Max builds one for every subject on your profile, and each exam board stays on its own shelf.
The Resource Vault
Per-subject question desks, your own full-marks rewrites collected in one place, live diagram pads and sprint packs — the desk this whole page has been showing you, with everything on it.
Priority marking
The same second-opinion depth, run at higher concurrency, so a long script comes back sooner. It matters most in the week you are marking a whole paper a day.
The Sunday examiner coach
The weekly email in full. This is the one thing on this page that Scholar does not include at all.
Credits to start, and again before the exam
25 bonus credits the day you start, and another 15 when your exam comes inside 14 days — off the date you set yourself, not a timer we made up.
250 questions a month
Against 120 on Scholar. Enough to mark every question you write in an exam term without ever thinking about it.

Most students do not need this — Scholar covers one subject properly and is what we would pick. Max is worth it if you are marking across three or four subjects at once.

Everything in this panel is Max only. Scholar keeps the marking, the map, the trajectory, the drills and the lessons — it does not get the vault, the weekly email or priority marking.

What this much marking costs elsewhere

A private tutor charges £30–50 an hour and works through roughly one answer in that time.

Aisha marked 18 in 7 weeks, each one against the official scheme, each one back in about three minutes. A Scholar plan covers 120 questions a month — more in four weeks than she got through in 7.

Everything you just saw, as a list

What you get on each plan

	Free$0	Scholar$19.99/mo	Max$35/mo
Marked against the official scheme	✓	✓	✓
A reason for every mark, in the margin	✓	✓	✓
Course notes and live diagrams	✓	✓	✓
Lesson flashcards, concept map, practice	—	✓	✓
Your answer rewritten to full marks	—	✓	✓
Second opinion on long scripts	—	✓	✓
Topic mastery map	—	✓	✓
Grade trajectory and prediction	—	✓	✓
Next question picked for you	—	✓	✓
Resource vault	—	1 subject	All
Weekly examiner email	—	—	✓
Priority marking	—	—	✓
Questions marked per month	5	120	250

Marking whole papers weekly? That is Scholar — $19.99 a month, or $199 for the whole exam year.

Priced in US dollars and converted at checkout. Cancel whenever you like — everything you marked stays in your account either way.

Pick a plan Or mark one free first

What it takes to see this on your own account

Eighteen scripts. That is the whole trick.

Everything above was computed from Aisha’s marked answers — the map, the trajectory, the fact that Differential equations is what stands between her and an A, 5 points away. None of it was written by us. Mark your own questions and the same page fills in with your topics, your gaps and your deadline.

Mark a question — free See plans

No card, and no account needed for the first one. The ink and the per-mark breakdown are free, always — paid adds the route: the rewrite, the drills, the mastery map and the weekly report.