# Calculus Gacha！ vs Fluid Mechanics Practice

The clearest difference is price: Calculus Gacha！ at Free against Fluid Mechanics Practice's $0.49. Calculus Gacha！ also leads on update cadence (every 3 days vs every 6 days). Fluid Mechanics Practice's advantage is in-app purchases (none vs 4) and iOS requirement (13.0 vs 15.0). On ads and device support there is nothing between them.

Calculus Gacha！ is free to download; Fluid Mechanics Practice costs $0.49 up front. Calculus Gacha！ sells 4 one-off in-app purchases. Fluid Mechanics Practice asks for nothing beyond the download.

Calculus Gacha！ ships an update every 3 days, Fluid Mechanics Practice every 6 days. The most recent releases landed on October 30, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | Calculus Gacha！ | Fluid Mechanics Practice |
| --- | --- | --- |
| Price | **Free** | $0.49 |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 3 days** | Every 6 days |
| Size | 83 MB | 24 MB |
| Requires iOS | 15.0 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Shunsuke Nakamura](https://appshunter.io/developer/1828229182) | [Manish Kumar](https://appshunter.io/developer/1854995154) |

## What reviewers say

### Calculus Gacha！

[App page](https://appshunter.io/ios/app/calculus-gacha/id6753078774)

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 不定方程式ガチャ利用オプション | $0.99 | one-time |
| AI Tutor Pass | $2.99 | one-time |
| AI Tutor Plus(500) | $2.99 | one-time |
| 履歴管理機能オプション | $2.99 | one-time |


### Fluid Mechanics Practice

[App page](https://appshunter.io/ios/app/fluid-mechanics-practice/id6757950639)

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

**In-app purchases:** none


## Frequently asked questions

### Is Calculus Gacha！ free?

Calculus Gacha！ is free to download, with in-app purchases available.

### Is Fluid Mechanics Practice free?

Fluid Mechanics Practice costs $0.49, with no in-app purchases.

### Do Calculus Gacha！ or Fluid Mechanics Practice have ads?

Neither Calculus Gacha！ nor Fluid Mechanics Practice shows ads.

### Which is updated more often, Calculus Gacha！ or Fluid Mechanics Practice?

Calculus Gacha！ ships an update every 3 days, and Fluid Mechanics Practice every 6 days. Most recently, Calculus Gacha！ was updated on October 30, 2026 and Fluid Mechanics Practice on October 28, 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.*