The Devil's Calculator vs 4=10
Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.
The Devil's Calculator
This math puzzle game challenges you to decipher obscure operators on a calculator. Solve algebraic puzzles by working backward to understand the functions and purge the calculator of its demons. It's an addictive and educational experience with user-created levels and DLC.
- Obscure operator deciphering
- Algebraic puzzle solving
- User-created levels
- DLC levels by mathematicians
- Graphing mechanics
- Hand-drawn artwork
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An evil calculator has its normal arithmetic operators replaced with sadistically obscure functions. Using logic and algebraic puzzle solving, you must work backwards to interpolate them and purge the calculator of its demons. Non-profit and open-source, The Devil's Calculator is a highly original indie game that's as addicting as it is educational. Accessible to numberphiles and math novices alike, the first 20+ levels are 100% free to play and enjoy along with several DLC levels, authored by famous mathematicians like Alex Bellos, Grant Sanderson, James Grime, Tony Padilla and James Tanton! The game was named a fan favorite of GDWC, and one of the top 10 indie games of 2019 by PAX. Each level has you decipher the function of a mysterious operator and use it to calculate the number of the beast to progress. Advanced graphing mechanics, countless features and simple, yet innovative level design provide considerable depth to the gameplay. Players unlock the ability to create their own levels and play challenges others have created - including free DLC levels crafted by the game's creators, educators and mathematicians. With hand drawn artwork and a charming story, the Devil's Calculator is a genuinely fun and gratifying puzzle experience. The game was celebrated at the MOVES conference by the National Museum of Mathematics in New York City. Cinq-Mars Media is a 501(c)(3) non-profit organization developing technology to support scientific research related to human safety and education, and to make such technology and research available on a charitable basis.
4=10
A casual number puzzle game for all ages. Combine four given numbers using basic math operations to reach the target of 10. It offers a relaxing experience that improves mental math skills and number familiarity.
- Combine four numbers to equal 10
- Basic math operations
- Gradually increasing difficulty
- One-handed play
- Improves mental math skills
- Relaxing and soothing gameplay
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4=10 is a simple number puzzle game suitable for all ages. The objective is to use four given numbers and combine them in an expression that equals 10. For example, you can solve it by adding 1, 2, 3, and 4 together (1+2+3+4=10). The game relies on basic math operations and starts off easy, gradually increasing in difficulty. It's designed to be a relaxed and soothing experience. You can play it with just one hand, using your phone whenever and wherever you like. By playing this game, you'll become more comfortable with numbers and improve your basic math skills, including mental calculations, using parentheses, and following the correct order of operations. Enjoy the game and happy calculating! :)
Screenshots
Verdict
The clearest difference is update cadence: The Devil's Calculator at every 10 days against 4=10's every 2 months. The Devil's Calculator also leads on iOS requirement (10.0 vs 12.0). 4=10's advantage is ratings volume (2.6K vs 245) and review sentiment (98% vs 87%). On price, rating, ads and in-app purchases 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. The Devil's Calculator sells 1 one-off in-app purchase and 4=10 sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
On the App Store both sit at effectively the same score — 4.8 for The Devil's Calculator against 4.9 for 4=10. That said, the two scores are not equally well evidenced: 4=10 has 2.6K ratings behind it against 245, so its average is the more settled of the two. Written reviews are what separate them: 87% of The Devil's Calculator's written reviews are positive against 98% of 4=10's.
The Devil's Calculator ships an update every 10 days, 4=10 every 2 months. The most recent releases landed on October 16, 2026 and October 17, 2026 respectively.
| Parameter | The Devil's Calculator | 4=10 |
|---|---|---|
| Price | Free | Free |
| Rating | 4.8 (245 ratings) | 4.9 (2.6K ratings) — better |
| Positive reviews | 87.2% of reviews | 97.9% of reviews — better |
| Number of ratings | 245 | 2.6K — better |
| Update frequency | Every 10 days — better | Every 2 months |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 10.0 — better | 12.0 |
| Further details — not scored | ||
| Size | 77 MB | 33 MB |
| Age rating | 4+ | 4+ |
| Developer | Cinq-Mars Media | Sveinn Steinarsson |
Customer experience
The Devil's Calculator
4=10
User reviews
The Devil's Calculator
From 245 App Store ratingsWhat we love
- 💡 Most creative idea ever
- 🧠 Genius puzzle design
- 👍 Fun and educational
- 🚀 Brilliant game concept
- 🤓 Great for math lovers
Room to improve
- 😠 Tedious late puzzles
- 🐛 Calculator responsiveness issues
- 🐛 Wolfram graphing feature doesn't work
- 🐛 Progress saving issues
- 🐛 Calculator malfunction
4=10
From 2.6K App Store ratingsWhat we love
- 👍 Simple and fun
- 🧠 Helps improve math skills
- 🔒 No ads or in-app purchases
- 💡 Challenging yet relaxing
Room to improve
- 🤔 Some levels too easy
- 🤯 Can get repetitive at times
Bugs and requests
The Devil's Calculator
Reported bugs
9 issues- Some late puzzles with the third operator get too tedious with too much trial and error
- The built-in calculator needs some work and button responsiveness isn’t always the best.
- The graph to wolfram alpha function doesn’t seem to work.
- There’s unfortunately an exploit I accidentally discovered that allows you to bypass any level.
- The “real” calculator malfunctions when you want to use the answer you got previously, like if I input “330 * 2”, getting 660, then pressed “+6” on the next row, instead of showing 660 + 6 = 666, it’d show 2+6 = 8
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- Lost progress again from 38 to 33. iPhone XS Max, iOS 12.4.1.
- My progress seems to be undone somewhat arbitrarily. I was working through the 50s, and when I booted up the game today, my progress had reset to level 35.
- The wolfram graphing feature doesn’t work.
- There’s a problem with DLC LEVEL 6 however.
Requested features
3 requests- Update the app
- Fix DLC Level 6
- More levels
4=10
Reported bugs
1 issue- None reported
Requested features
2 requests- Add more difficulty levels
- Introduce new gameplay modes
In-app purchases
The Devil's Calculator
- Full Version of Game$2.99
4=10
- 4≠10 add-on$3.99








