# Even or odd Mental calculation vs 2357!

The clearest difference is in-app purchases: 2357! at none against Even or odd Mental calculation's 1. 2357! also leads on ads (none vs shown) and update cadence (every 2 weeks vs every 23 months). Even or odd Mental calculation's advantage is review sentiment (100% vs 89%). On price and device support there is nothing between them.

Both are free to download. Even or odd Mental calculation sells 1 one-off in-app purchase. 2357! asks for nothing beyond the download.

Even or odd Mental calculation ships an update every 23 months, 2357! every 2 weeks. The most recent releases landed on November 1, 2026 and November 2, 2026 respectively.

## The numbers

| Metric | Even or odd Mental calculation | 2357! |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.0 (3 ratings)](https://appshunter.io/ios/app/2357/id1079318619/reviews)** |
| Number of ratings | — | **3** |
| Positive reviews | **100.0% of reviews** | 89.5% of reviews |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 23 months | **Every 2 weeks** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 68 MB | 156 MB |
| Requires iOS | 15.0 | **7.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Iker Vazquez](https://appshunter.io/developer/1032978250) | [HANAUTA INC.](https://appshunter.io/developer/492009717) |

## What reviewers say

### Even or odd Mental calculation

[App page](https://appshunter.io/ios/app/even-or-odd-mental-calculation/id1032978251)

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:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full version upgrade | $0.99 | one-time |


### 2357!

[App page](https://appshunter.io/ios/app/2357/id1079318619)

Engage in a fast-paced division battle game where you destroy target numbers using prime factor combinations within a 60-second time limit. Improve your calculating skills and compete globally in this brain-training puzzle.

**Highlights:** 60-second division battles, Destroy target numbers with prime factors, Score multipliers for simultaneous throws, Global ranking competition, Brain training and calculation skill improvement, Intuitive and easy one-hand play

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Even or odd Mental calculation free?

Even or odd Mental calculation is free to download, with in-app purchases available.

### Is 2357! free?

2357! is free to download, with no in-app purchases.

### Do Even or odd Mental calculation or 2357! have ads?

Even or odd Mental calculation shows ads; 2357! does not.

### Which is updated more often, Even or odd Mental calculation or 2357!?

Even or odd Mental calculation ships an update every 23 months, and 2357! every 2 weeks. Most recently, Even or odd Mental calculation was updated on November 1, 2026 and 2357! on November 2, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*