Earth Explore vs lemma
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Earth Explore
Identify bird songs using artificial intelligence with this application. It can classify over 2000 bird species globally, all processed directly on your device without an internet connection.
- AI-powered bird song classification
- Supports over 2000 bird species
- Offline functionality
- On-device processing
- Global bird song database
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Use this app to classify bird songs! Using artificial neural networks, the application can classify the song of over 2000 different birds from around the world. And with no need to connect to any remote server, this app can run all of its classifications on your phone, without connection to the internet.
lemma
This app provides focused, daily practice for quantitative interviews, featuring timed sprints of math and probability problems. It tracks your skill across disciplines with adaptive difficulty and offers hints and solutions to help you improve. Designed for those preparing for trading firm interviews or seeking to build a quantitative thinking habit.
- Daily timed problem sprints
- Per-category ELO skill tracking
- Adaptive difficulty
- Hints and step-through solutions
- Streaks, XP, and achievements
- Leaderboard
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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. — 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/
Screenshots
Verdict
The clearest difference is in-app purchases: Earth Explore at none against lemma's 3. lemma's advantage is ads (none vs shown). On price, rating, ratings volume and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. lemma sells 3 in-app purchases, starting at $6.99 per 7 days. Earth Explore asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 5.0 for Earth Explore against 5.0 for lemma. Both are backed by a comparable volume of ratings — 1 and 1 respectively.
| Parameter | Earth Explore | lemma |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) | 5.0 (1 ratings) |
| Number of ratings | 1 | 1 |
| Update frequency | — | Every 3 days |
| Ads | Yes | No — better |
| In-app purchases | No — better | Yes |
| Monetization | Ad-supported — better | Free with in-app purchases |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.5 | 15.1 — better |
| Further details — not scored | ||
| Size | 104 MB | 31 MB |
| Age rating | 4+ | 12+ |
| Developer | Cameron Ryan | Roger You |
Customer experience
Earth Explore
lemma
In-app purchases
Earth Explore
No in-app purchases
lemma
- Lemma Premium$6.997 Days
- Lemma Premium$9.991 Month
- Lemma Premium3 Days trial$59.991 Year









