Your math notes, rebuilt as a lesson you can play with.
Photos, PDFs or typed notes become worked examples you reveal step by step, graphs you can move, and practice that checks your answers.
30 credits freeno card neededbuilt by a math tutor
Messy notes in. A real lesson out.
A page of Calculus I notes, question marks and all, and the lesson made from them, running live in the same locked-down viewer your lessons use. Try a practice problem: nothing you do here is saved.
The notes
Calc 1 — Derivative rulesCh 3.1–3.4 · my notes
Power rule: d/dx [xn] = n xn-1
ex: d/dx [x5] = 5x4
ex: d/dx [1/x2] = -2x-3 = -2/x3
Product rule: (fg)' = f'g + fg'
ex: d/dx [x2 sin x] = 2x cos x <- check this one??
Quotient rule: (f/g)' = (f'g - fg') / g2
"low d-high minus high d-low, over low squared"
Chain rule: d/dx f(g(x)) = f'(g(x)) · g'(x)
ex: d/dx [(3x + 1)4] = 12(3x + 1)3
Prof said: always simplify!!
Quiz Friday — tangent lines: y - f(a) = f'(a)(x - a)
It even answers the “check this one??”: that product-rule example was wrong, and the lesson shows the fix.
The lesson
From notes to lesson in three steps
Step 1: Upload your notes
Paste typed notes, or add photos of handwritten pages, PDFs or a worksheet with blank problems. Tell us if you want to focus on something specific.
Step 2: Pick Quick practice or Full study guide
Quick practice (from 15 credits) is a short refresher with lots of practice problems. Full study guide (from 45 credits) covers every idea in your notes, like a tutor would. You see the exact price before you click.
Step 3: Study an interactive lesson
Work through it at your own pace. It's saved in your library with your progress, so you can come back before the test.
Everything a good tutor would hand you
Every lesson is one interactive page, made from your notes and built to be studied, not just read.
1. Progress you can see. A progress bar with a check for every finished section, and points (XP) for correct answers that count toward your streak.
2. Built from your notes. Examples from your own notes are labeled "From your notes" and use your teacher's notation.
3. Step-by-step worked examples. Solutions appear one step at a time behind "Show next step", so you try first and only peek when you're stuck.
4. Interactive visuals. Sliders, graphs and diagrams you can move, for the ideas that click once you see them change.
5. Practice with hints and instant checking. A hint first, then the steps, then the answer.
6. A concept check. Quick multiple-choice questions with an explanation for every option.
7. Cheat sheet + mistakes that cost points. The key formulas and steps on one page, plus the common slip-ups to watch for on the test.
8. A mastery summary. At the end: your score, the XP you earned and exactly what to review, with links back to it.
1. Progress you can see
A progress bar with a check for every finished section, and points (XP) for correct answers that count toward your streak.
2. Built from your notes
Examples from your own notes are labeled "From your notes" and use your teacher's notation.
3. Step-by-step worked examples
Solutions appear one step at a time behind "Show next step", so you try first and only peek when you're stuck.
4. Interactive visuals
Sliders, graphs and diagrams you can move, for the ideas that click once you see them change.
5. Practice with hints and instant checking
A hint first, then the steps, then the answer. Type your answer and it's checked right away (fractions and decimals both count).
6. A concept check
Quick multiple-choice questions with an explanation for every option.
7. Cheat sheet + mistakes that cost points
The key formulas and steps on one page, plus the common slip-ups to watch for on the test.
8. A mastery summary
At the end: your score, the XP you earned and exactly what to review, with links back to it.
Works for any math class
High school or college, plus the math inside other subjects.
- Pre-algebra
- Algebra 1 & 2
- Geometry
- Trigonometry
- Precalculus
- Calculus I, II & III
- AP Calculus AB & BC
- Statistics
- AP Statistics
- Linear algebra
- Differential equations
- Discrete math & proofs
- Physics & engineering math
- Economics math
Built by a math tutor
I'm a math major and a math tutor. Almost every week, a student brings me a page of notes they copied down in class, and they can't study from it. The steps that made sense on the board don't make sense at home.
So I built Lemma to do what I do in a tutoring session: start with why an idea works, walk through the problems from your own notes one step at a time, then give you practice that tells you right away whether you've got it.
Accuracy comes first. A study guide with a wrong answer is worse than no study guide, so every lesson is made with the instructions I'd give myself: work every problem completely, double-check every step, and use your notation. If you ever spot a mistake, every lesson has a "Report a mistake" button, and those reports come straight to me.
Thomas, founder of Lemma
For parents
The short version of what matters when your teen signs up. The FAQ, pricing and privacy pages have the details.
Notes are deleted
Uploaded notes are deleted once the lesson is made. Lessons stay private to the student's account.
13 and older
Accounts are for students who are 13 or older.
Credits come back
If a lesson can't be made, the credits go back to the account automatically.
Cancel any time
The weekly, monthly and yearly plans can be cancelled any time from the account page.
Report a mistake
Every lesson has a "Report a mistake" button that sends the problem to us to check.
Free to start. A plan when you need more.
Every new account gets 30 credits. After that, $15 a month buys 180 credits, about $1.25 per Quick practice lesson. You always see a lesson's price before you make it.
Free to start
Available now$0
30 credits when you sign up
Monthly plan
Available now$15/month
180 credits every month
About $1.25 per Quick practice lesson
Also weekly ($5) or yearly ($150, 17% off)
Top-up packs
Available now$5and up
Extra credits when you need them
Questions students ask
What happens to the notes I upload?
Your notes are private to your account. We use them only to make your lesson.
Once your lesson is made, the files you uploaded are deleted. The lesson itself stays in your library until you delete it.
You can delete any lesson from your library. "Delete my account and data" on the Account page removes everything: your notes, lessons, progress and credit history.
Lessons are written by an AI model (Claude, made by Anthropic) following teaching instructions written by a math tutor. To make your lesson, your notes are sent to Anthropic for that one job. The way we use Anthropic's service, your notes aren't used to train AI models.
Which subjects does it work for?
Any math or math-related class: pre-algebra, algebra, geometry, trigonometry, precalculus, calculus (including AP Calculus AB and BC, and multivariable calculus), statistics (including AP Statistics), linear algebra, differential equations, discrete math and proofs.
The math in other classes works too, like physics, engineering, chemistry and economics. High school and college notes are both welcome.
Are the lessons accurate?
Accuracy is the whole point. Every lesson is made with instructions to work each problem completely and double-check every step before writing it. If your notes contain a mistake, the lesson points it out gently and shows the fix.
Still, no study guide is perfect. If something looks off, check it against your textbook or ask your teacher, and use the "Report a mistake" button on the lesson so we can fix it.
What's the difference between Quick practice and Full study guide?
Quick practice (from 15 credits) is short: a quick refresher on the main ideas, then lots of practice problems with hints and answer checking, a short concept check and a cheat sheet. Great the night before a quiz.
Full study guide (from 45 credits) covers every idea in your notes: why it works, a step-by-step method, worked examples, interactive visuals, more practice, a longer concept check, a full cheat sheet and a list of mistakes that cost points. Great for unit tests and finals.
Got a test coming up? Start with the notes you already have.
Your first lessons are free: 30 credits, no card needed.
Make a lesson free