Comparison

Euclidea vs Even or odd Mental calculation

Price, ratings, monetisation and update history for both games, side by side — with what reviewers say about each.

Head to head
About

Euclidea

Engage in geometric construction puzzles based on Euclidean principles. Solve increasingly difficult challenges using innovative tools, with options to explore, get hints, and compete with friends. Unlock new levels by earning stars or purchase an in-app item to remove restrictions.

Highlights
  • 156 geometric puzzle levels
  • 10 innovative construction tools
  • Explore mode with hints
  • Dynamic drag, zoom, and pan interface
  • Game Center competition
  • Unlockable tools and shortcuts
Features
Read full description

Euclidea is geometrical puzzles based on classical Euclidian constructions. > 156 Levels: from very easy to really hard > 10 Innovative Tools > "Explore" Mode and Hints > Easily Drag, Zoom & Pan > Compete with Friends via the Game Center > No Advertising! New levels are unlocked as you solve the previous ones. You can complete the whole game only if you earn all the stars (L, E, and V). But you can buy an IAP that removes this restriction. Find more useful hints on Euclidea on our site: https://www.euclidea.xyz/faq. “Euclidea has been shown to help with imagination, intuition, and logic, all wonderful skills to develop.” – appPicker “Euclidea is an absolute joy to play…it’s a game that every math student should have and, in an ideal world, every adult should like.” – Non-Trivial Games ***About Euclidea*** Euclidea is a brilliantly original way to learn about, explore and have fun with Euclidian Constructions! Your task is to solve interesting challenges by building geometric constructions with a straightedge and compass. If you design the most elegantly simple solutions in the least number of moves, you’ll earn the highest scores. Solutions are scored in lines (L) and elementary Euclidean constructions (E). ***Start Simple and Get Smarter!*** Don’t worry if you aren’t a math wizard. Euclidea starts out with simple challenges that guide you through the basics. Once you master the fundamentals, you’ll move on to tougher, more mind-bending challenges such as inner/outer tangents, regular polygons, and more. There are 120 unique challenges in total, which are organized in packs for simpler navigation. ***Add Constructions to Your Interface*** When you learn certain significant constructions – such as angle bisectors, non-collapsing compass, and so on – they are automatically added to the Euclidea interface’s shortcut, which helps you save time and allows you to create clean, uncluttered drawings. ***Easily Drag, Pan & Zoom*** Euclidea-created constructions are completely dynamic. As such, you can drag to adjust angles, lines, radii and so on. You can also easily zoom and pan. This not only makes the experience more interactive, but it allows you to more deeply grasp the relationships between geometric elements, explore various possibilities, and analyze errors. ***Instant, Automatic Precision*** Don’t worry about spending time or effort trying to achieve perfect precision, because Euclidea automatically handles that task by pinning points, lines and circles to the app’s clean interface. ***Compete with Friends*** Who said that math isn’t a competitive sport? Challenge your friends to see who can come up with the most elegant solutions, and track your achievements and rankings via the Game Center. ***Additional Special Features*** > A helpful “Explore” mode that allows you to see the figure you need to construct > An inventory of tools that you create as you progress – you’ll need these to solve future challenges > Some challenges can be solved in more than one way, which means you can try a different approach and have even more fun ***Questions? Comments? Send in your inquiries and stay up-to-date on the latest Euclidea news at https://www.euclidea.xyz/

About

Even or odd Mental calculation

Test your mental math skills by quickly determining if the result of an on-screen operation is even or odd. Earn more points for faster answers and challenge friends to see who has the quickest mind. The difficulty increases as you progress.

Highlights
  • Timed mental calculation challenges
  • Score tracking for personal bests
  • Speed-based scoring system
  • Increasing difficulty levels
  • Multiplayer comparison
Features
Read full description

Solve the calculation and choose: is the answer even or odd? Par o Impar combines addition, subtraction and multiplication with short sessions and two large answer buttons. Practise at your own pace or test your speed across five modes: - Classic: answer before time runs out and try to beat your record. - Sprint 60: get as many answers right as you can in one minute. Each mistake costs three seconds. - Daily Challenge: 20 calculations each day, with one official attempt and unlimited practice afterwards. - Training: choose addition, subtraction, multiplication or a mix. Play without a timer and see an explanation after each answer. - Challenge Route: complete 30 levels involving calculations, accuracy and memory, and earn medals. A short tutorial explains the controls. Pause your game, adjust sound and vibration, and check your records. Progress is saved on this device and all game modes work offline. The game interface is in Spanish. The app contains advertising. If you previously bought ad removal on iOS, you can restore it from Settings (Ajustes).

Screenshots

Euclidea4 screens
Even or odd Mental calculation4 screens

Verdict

The call

The clearest difference is ads: Euclidea at none against Even or odd Mental calculation's shown. Euclidea also leads on update cadence (every 3 months vs every 23 months) and iOS requirement (8.0 vs 15.0). Even or odd Mental calculation's advantage is review sentiment (100% vs 86%). On price, in-app purchases, monetization model 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Euclidea sells 6 one-off in-app purchases and Even or odd Mental calculation sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Euclidea ships an update every 3 months, Even or odd Mental calculation every 23 months. The most recent releases landed on October 29, 2026 and October 20, 2026 respectively.

Scorecard4 real differences · 6 level
Euclidea versus Even or odd Mental calculation: the parameters behind the verdict, then further details
ParameterEuclideaEven or odd Mental calculation
PriceFreeFree
Rating4.8 (938 ratings) — better—
Positive reviews86.1% of reviews100.0% of reviews — better
Number of ratings938 — better—
Update frequencyEvery 3 months — betterEvery 23 months
AdsNo — betterYes
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS8.0 — better15.0
Further details — not scored
Size223 MB68 MB
Age rating4+4+
DeveloperHORIS INTERNATIONAL LIMITEDIker Vazquez

Customer experience

Euclidea

All ratings937 ratings
Positive96.5%
Neutral1.2%
Negative2.3%
Written reviews397 reviews
Positive86.1%
Neutral3.5%
Negative10.3%

Even or odd Mental calculation

Written reviews5 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Bugs and requests

Euclidea

Reported bugs

3 issues
  • App crashing on launch
  • Circle tool not snapping to points
  • Solutions not being accepted correctly

Requested features

5 requests
  • Offline mode support
  • Ability to mark points on free draw
  • Protractor feature
  • More supplemental educational content
  • Ability to see when multiple solutions exist

Even or odd Mental calculation

Not enough reviews yet to summarise bugs or requests.

In-app purchases

6 purchases

Euclidea

One-time6
  • Unlock the Rest Levels$0.99
  • Unlock the Rest Hints$0.99
  • Thanks to developers$0.99
Show 3 more
  • Night Mode$0.99
  • Many thanks to developers$4.99
  • Many, many thanks to developers$49.99
1 purchases

Even or odd Mental calculation

One-time1
  • Full version upgrade$0.99

Questions

Is Euclidea free?
Euclidea is free to download, with in-app purchases available.
Is Even or odd Mental calculation free?
Even or odd Mental calculation is free to download, with in-app purchases available.
Do Euclidea or Even or odd Mental calculation have ads?
Even or odd Mental calculation shows ads; Euclidea does not.
Which is updated more often, Euclidea or Even or odd Mental calculation?
Euclidea ships an update every 3 months, and Even or odd Mental calculation every 23 months. Most recently, Euclidea was updated on October 29, 2026 and Even or odd Mental calculation on October 20, 2026.

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