# あかほん！ プロトタイプA vs ProbabilityPlayer

The clearest difference is in-app purchases: あかほん！ プロトタイプA at none against ProbabilityPlayer's 1. あかほん！ プロトタイプA also leads on iOS requirement (7.0 vs 18.0). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. ProbabilityPlayer sells 1 one-off in-app purchase. あかほん！ プロトタイプA asks for nothing beyond the download.

あかほん！ プロトタイプA ships an update every 4 weeks, ProbabilityPlayer monthly. The most recent releases landed on September 21, 2026 and September 27, 2026 respectively.

## The numbers

| Metric | あかほん！ プロトタイプA | ProbabilityPlayer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/a/id1438322285/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 4 weeks** | Monthly |
| Monetization | **Free** | Free with in-app purchases |
| Size | 88 MB | 9 MB |
| Requires iOS | **7.0** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Nobumitsu Shikine](https://appshunter.io/developer/1361521847) | [Motonari Hibi](https://appshunter.io/developer/386737172) |

## 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


### ProbabilityPlayer

[App page](https://appshunter.io/ios/app/probabilityplayer/id6737689746)

Practice probability problems for the Kyotsu Test, a common Japanese university entrance exam. This app focuses on mathematical probability questions and includes diagrams to aid understanding. It is designed to help students prepare for this specific academic assessment.

**Highlights:** Probability problem practice, Kyotsu Test focus, Mathematical probability, Diagrams included, University entrance exam prep

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium | $1.99 | one-time |


## 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 ProbabilityPlayer free?

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

### Do あかほん！ プロトタイプA or ProbabilityPlayer have ads?

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

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

あかほん！ プロトタイプA ships an update every 4 weeks, and ProbabilityPlayer monthly. Most recently, あかほん！ プロトタイプA was updated on September 21, 2026 and ProbabilityPlayer on September 27, 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.*