lemma: Comp Math Trainer
AMC, AIME, IMO, Putnam
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Train like a quant. Daily.
Lemma is the focused, no-fluff prep app for quantitative interviews — built for students and grads targeting Jane Street, Citadel, Optiver, Two Sigma, and the rest of the trading-firm gauntlet.
WHAT'S INSIDE WITH YOUR SUBSCRIPTION
• Daily sprints — bite-sized timed sets of mental math, probability, combinatorics, expected value, and market-making problems
• Per-category ELO — your skill is tracked across 10 disciplines, from Novice to Expert
• Adaptive difficulty — problems chosen to keep you at the edge of your level, not above or below
• Hints + step-through solutions — get unstuck without giving up
• Streaks, XP, leagues — habit loops without the noise
• Achievements — unlock as you grind
• Leaderboard — see how you stack up
WHO IT'S FOR
• CS / math undergrads applying to trading firms
• Recent grads prepping for technical interviews
• Self-learners who want a daily quantitative-thinking habit
• Anyone curious about how trading interviews actually feel
WHY LEMMA
We strip out the gamified clutter and keep what matters: hard problems, fast iteration, real numbers on your progress. The interface borrows more from a Bloomberg terminal than a typical mobile game — monospaced metrics, hairline borders, dark by default.
Most prep books drown you in 800 pages. Most courses lock you in for months. Lemma is 10 minutes a day, sharpened every day.
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Lemma offers an optional auto-renewable subscription for unlimited daily sprints and premium problem sets. Subscriptions auto-renew unless cancelled at least 24 hours before the end of the current period. Manage or cancel anytime in your Apple ID settings.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://rogeru13.github.io/lemma-legal/privacy-policy/
Ratings & Reviews
- fixed problem sequences in workout
- adjusted problem solution UI to be more understandable
The developer, Roger You, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
- Contact Info
- Identifiers
- Usage Data
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Roger You
- Size
- 32.4 MB
- Category
- Education
- Compatibility
Requires iOS 15.1 or later.
- iPhone
Requires iOS 15.1 or later. - iPad
Requires iPadOS 15.1 or later. - iPod touch
Requires iOS 15.1 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
13+
- 13+
- Frequent
Contests
- In-App Purchases
Yes
- Lemma Premium $9.99
- Lemma Premium $59.99
- Lemma Premium $6.99
- Copyright
- © roger you