# あかほん！ プロトタイプA vs K

The clearest difference is price: あかほん！ プロトタイプA at Free against K's $0.99. あかほん！ プロトタイプA also leads on iOS requirement (7.0 vs 17.0). K's advantage is update cadence (every 2 weeks vs every 4 weeks). On ads, in-app purchases and device support there is nothing between them.

あかほん！ プロトタイプA is free to download; K costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

あかほん！ プロトタイプA ships an update every 4 weeks, K every 2 weeks. The most recent releases landed on October 8, 2026 and October 11, 2026 respectively.

## The numbers

| Metric | あかほん！ プロトタイプA | K |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/a/id1438322285/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 weeks | **Every 2 weeks** |
| Monetization | **Free** | Paid |
| Size | 88 MB | 4 MB |
| Requires iOS | **7.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Nobumitsu Shikine](https://appshunter.io/developer/1361521847) | [Masaki Kobayashi](https://appshunter.io/developer/1882180437) |

## What reviewers say

### あかほん！ プロトタイプA

[App page](https://appshunter.io/ios/app/a/id1438322285)

This app uses a unique story-driven approach to help users learn calculus concepts like differentiation. Follow characters through engaging dialogues that explain complex math topics at your own pace.

**Highlights:** Story-driven learning, Interactive dialogues, Calculus concepts (differentiation), Character-based guidance, NOVELICA system, Self-paced learning

**Features:** macOS Compatibility

**In-app purchases:** none


### K

[App page](https://appshunter.io/ios/app/k-mol-molecular-model/id6772762907)

Create and visualize 2D and 3D molecular models with intuitive drawing tools and AR capabilities. This app serves as a practical and cost-effective alternative to physical model kits for students.

**Highlights:** 2D structural formula drawing, 3D molecular model visualization, Augmented Reality (AR) viewing, Save and reopen models, Pre-built templates, Screenshot capture

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is あかほん！ プロトタイプA free?

あかほん！ プロトタイプA is free to download, with no in-app purchases.

### Is K free?

K costs $0.99, with no in-app purchases.

### Do あかほん！ プロトタイプA or K have ads?

Neither あかほん！ プロトタイプA nor K shows ads.

### Which is updated more often, あかほん！ プロトタイプA or K?

あかほん！ プロトタイプA ships an update every 4 weeks, and K every 2 weeks. Most recently, あかほん！ プロトタイプA was updated on October 8, 2026 and K on October 11, 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.*