# Summation vs The challenge is impossible

The clearest difference is in-app purchases: The challenge is impossible at none against Summation's 2. Summation's advantage is update cadence (every 3 weeks vs every 78 months) and iOS requirement (9.0 vs 12.0). On price, ads and device support there is nothing between them.

Both are free to download. Summation sells 2 one-off in-app purchases. The challenge is impossible asks for nothing beyond the download.

Summation ships an update every 3 weeks, The challenge is impossible every 78 months. The most recent releases landed on October 15, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | Summation | The challenge is impossible |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.2 (58 ratings)](https://appshunter.io/ios/app/summation/id1219879009/reviews)** | — |
| Number of ratings | **58** | — |
| Positive reviews | 70.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 78 months |
| Monetization | Free with in-app purchases | — |
| Size | 110 MB | 35 MB |
| Requires iOS | **9.0** | 12.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Lemon Jam Technology Co., Ltd.](https://appshunter.io/developer/884737211) | [志荣 胡](https://appshunter.io/developer/1057018236) |

## What reviewers say

### Summation

[App page](https://appshunter.io/ios/app/summation/id1219879009)

Engage your brain with a minimalistic math puzzle game. Rearrange numbers to solve increasingly challenging levels. Explore new themes and enjoy endless gameplay.

**Highlights:** Minimalistic math puzzle gameplay, Rearrange numbers to solve puzzles, Endless levels for infinite play, Unlockable game themes, Brain workout challenges

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Buy Hints | $0.99 | one-time |
| Remove Ads | $1.99 | one-time |

**What reviewers like**

- 🧠 Engaging puzzle mechanics with unique crossword-style addition gameplay
- 😌 Relaxing and calming experience without timers or move counters
- 🎨 Beautiful minimalist design with clean aesthetic
- 🎵 Pleasant soundtrack and sound design
- 📈 Good difficulty progression that challenges without frustrating

**What reviewers complain about**

- 📺 Excessive and intrusive full-screen video advertisements
- 💰 Ads persist even after paying for ad-free version
- 🔄 Ads interrupt gameplay and timer continues during Challenge Mode
- 🛑 Frequent app crashes and freezes, often related to ads
- 🔗 App Store opens unexpectedly multiple times during gameplay

**Reported bugs**

- Hint button freezes game and requires reinstall to fix
- Game crashes at specific levels (e.g., level 102)
- App crashes immediately upon opening with blue dot indicator
- Full-screen ads cannot be closed and trap users
- Game gets stuck in landscape mode after full-page ad

**Requested features**

- Dark mode for nighttime playing
- Multiplication puzzle variant
- Increased difficulty progression beyond level 100
- More varied puzzle structures and mechanics
- Ability to purchase larger quantities of hints at once


### The challenge is impossible

[App page](https://appshunter.io/ios/app/the-challenge-is-impossible/id1384619971)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Summation free?

Summation is free to download, with in-app purchases available.

### Is The challenge is impossible free?

The challenge is impossible is free to download, with no in-app purchases.

### Do Summation or The challenge is impossible have ads?

Neither Summation nor The challenge is impossible shows ads.

### Which is updated more often, Summation or The challenge is impossible?

Summation ships an update every 3 weeks, and The challenge is impossible every 78 months. Most recently, Summation was updated on October 15, 2026 and The challenge is impossible on October 8, 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.*