- Q12/5Adds numerators and denominators
- Q32x + 4Multiplies only the first term in the bracket
For secondary mathematics
Show teachers where understanding breaks down.
LessonSpindle helps schools and tutorial centres find the misconceptions behind wrong answers. AI reads written working and question-level results, then suggests revision groups and practice from approved materials — for teachers to review.
A proposed product. The marking room runs in your browser on a fictional class.
Chidi · SS2 GoldWeek 6 check-in
1. Work out ½ + ⅓
1 + 1 = 2
2 + 3 = 5 → 2/5
adds the tops and the bottoms
2. Solve 3x + 5 = 20
x + 5 = 20 ÷ 3
divides before subtracting
The problem
The same mark can hide different problems.
Three students score 2 out of 4 on the same quiz. A mark book shows three identical results. Their working shows three different things to teach.
- Q12/6Finds a common denominator but doesn’t rescale numerators
- Q4−12Thinks a negative times a negative is negative
- Q12/5Adds numerators and denominators
- Q2x = 20/3 − 5Undoes operations in the wrong order
Fictional students and answers, from the class used in the marking room.
Misconception map
See the whole class at once.
Each row is a reasoning error from the rubric; each dot is a student whose working suggests it. Teachers see which ideas need reteaching for everyone and which need a small group.
Adding fractionsAdds numerators and denominators
5
Adding fractionsFinds a common denominator but doesn’t rescale numerators
3
Solving linear equationsUndoes operations in the wrong order
3
Solving linear equationsApplies an operation to one side only
2
Expanding bracketsMultiplies only the first term in the bracket
4
Multiplying negativesThinks a negative times a negative is negative
4
suggested low confidence, check firstBefore teacher review · fictional class of 12
How it works
From a pile of scripts to tomorrow’s lesson.
- 1
Scan the working
Upload photos or scans of answer scripts, or question-level results from your existing tests.
- 2
Read against the rubric
Each wrong answer is compared with the reasoning errors in your explicit marking rubric, with a confidence score.
- 3
Teacher reviews
Confirm, change or reject every interpretation. Unclear handwriting and low-confidence readings come first.
- 4
Group and choose practice
Students who share a reviewed misconception are grouped, with practice drawn only from materials you approved.
- 5
Approve, then share
Nothing reaches a student until a teacher has approved the group’s feedback and practice.
Revision groups
Small groups, with practice from your own materials.
Groups form from reviewed misconceptions, not from overall marks. Practice is chosen from your department’s approved question bank, never generated and sent on its own.
Adding fractions
Adds numerators and denominators
Amaka · Chidi · Gift · Ifeanyi · Lami
P-01 · Concrete
Shade 1/2 and 1/3 of the same bar. What fraction is shaded altogether?
Waiting for teacher approval
Multiplying negatives
Thinks a negative times a negative is negative
Bolu · Efe · Gift · Kemi
P-10 · Reasoning
Continue the pattern: 3 × −4 = −12, 2 × −4 = −8, 1 × −4 = −4, 0 × −4 = 0, −1 × −4 = ?
Waiting for teacher approval
Expanding brackets
Multiplies only the first term in the bracket
Amaka · Chidi · Gift · Jide
P-08 · Concrete
Use an area model to expand 3(x + 2).
Waiting for teacher approval
Ground rules
Built around the teacher’s judgement.
AI suggests. Teachers decide.
Every interpretation is a suggestion until a teacher confirms, changes or rejects it. Groups use reviewed answers only.
Only approved materials
Practice comes from a question bank your department has approved. LessonSpindle does not invent questions for students.
Nothing is shared without approval
Feedback and practice reach students only after a teacher approves them, group by group.
Honest about uncertainty
Messy handwriting and weak matches are flagged with their confidence, so teachers check them first.
A careless slip is not a misconception
Teachers can reject an interpretation with a reason, and that reasoning is kept in the log.
Initial scope
Starting with selected secondary maths topics.
The first version covers topics where a good marking rubric already spells out the common reasoning errors. Each school’s rubric is loaded before any scripts are read, and topics are added only once they’re tested with teachers.
Number
- Adding and subtracting fractions
- Directed numbers
- Percentages
Algebra
- Linear equations
- Expanding and factorising
- Substitution
Geometry
- Angles in polygons
- Pythagoras’ theorem
Why it matters
Many students fall behind in maths, and feedback can help.
Share of 15-year-olds below baseline proficiency in mathematics, on average across OECD countries.
OECD, PISA 2022 ResultsEducation systems where more than half of students scored below baseline proficiency in mathematics.
OECD, PISA 2022 ResultsEffect size often cited for feedback in Hattie’s research — though independent reviews of formative assessment in maths find smaller effects.
Kentucky Department of Education, evidence-based practice brief“Baseline proficiency” is PISA Level 2. Feedback effect sizes vary widely between studies and subjects.
Who it’s for
For the people who mark the scripts.
Secondary schools
Maths departments that want to know what to reteach after every test, not just who scored what.
Tutorial centres
Tutors who need to see each learner’s gaps quickly and plan focused sessions.
Exam preparation providers
Teams preparing large cohorts who need revision groups built from real errors.
Education networks
Groups of schools that want shared rubrics and a consistent view of where learning breaks down.
Pricing
Priced by students, not by teachers.
Illustrative pricing for a proposed product, to be agreed with pilot schools.
Department
$190per month
- Up to 300 students
- Two maths topics
- Misconception map and groups
- Practice from your question bank
School
$490per month
- Up to 1,200 students
- All available topics
- Head of department overview
- Exportable review log
Network
Custom
- Several schools or centres
- Shared rubrics and question banks
- Network-wide reporting
- Onboarding support
Proposed platform
Proposed architecture on AWS.
Not yet built. This website and the marking room run entirely in your browser.
- Amazon TextractReads text and handwriting from scanned answer scripts
- Amazon BedrockCompares working with rubric misconceptions and drafts feedback for review
- Amazon S3Stores scripts, rubrics and approved materials
- Amazon DynamoDBKeeps interpretations, reviews, groups and approvals
- AWS LambdaRuns the processing steps after each upload
Team
The founders of LessonSpindle.
Adesua Osagie
Founder/CEO
Adesua taught secondary mathematics and spent too many evenings working out why half a class got the same question wrong in different ways. She founded LessonSpindle and leads product and school partnerships.
Ibrahim Danjuma
Co-founder
Ibrahim leads the platform: reading scanned working, classifying likely reasoning errors against explicit rubrics, and making every interpretation easy for a teacher to check.
FAQ
Frequently asked questions.
Does LessonSpindle mark students’ work?
No. It suggests the likely reasoning behind wrong answers. Teachers review each suggestion, and marks stay with the teacher.
Which subjects and topics are covered?
Selected secondary maths topics with explicit rubrics, to start. Other topics are added once they are tested with teachers.
Where does the practice come from?
Only from question banks your school or centre has approved. LessonSpindle picks from them; it does not write questions for students.
Do students see anything automatically?
No. Feedback and practice are shared only after a teacher approves them.
Is LessonSpindle live?
Not yet. It is a proposed product; the marking room is a prototype running in your browser on a fictional class.
Pilot
Try it with one class and one topic.
A pilot starts with a single mathematics topic that already has an explicit marking rubric. Your teachers review every interpretation, decide the groups and approve every piece of feedback before students see it.
Or write to adesua@lessonspindle.site — Adesua Osagie replies personally.