# 学习成长21天 vs 几何星球

The clearest difference is in-app purchases: 学习成长21天 at none against 几何星球's 12. 学习成长21天 also leads on device support (3 vs 1) and iOS requirement (9.0 vs 17.0). 几何星球's advantage is update cadence (every 4 days vs weekly). On price and ads there is nothing between them.

Both are free to download. 几何星球 sells 12 one-off in-app purchases. 学习成长21天 asks for nothing beyond the download.

学习成长21天 ships an update weekly, 几何星球 every 4 days. The most recent releases landed on October 25, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | 学习成长21天 | 几何星球 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Weekly | **Every 4 days** |
| Size | 66 MB | 30 MB |
| Requires iOS | **9.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Guangdong Youyixue Education Technology Co., Ltd.](https://appshunter.io/developer/1508981243) | [Zenith Education Technology (Beijing) Co., Ltd.](https://appshunter.io/developer/1412589877) |

## What reviewers say

### 学习成长21天

[App page](https://appshunter.io/ios/app/21/id1518769944)

**In-app purchases:** none


### 几何星球

[App page](https://appshunter.io/ios/app/id6818393957)

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

**In-app purchases (12)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 视频导出买断 | $0.99 | one-time |
| 高频几何模型题库 | $1.99 | one-time |
| 圆的阴影面积题库 | $1.99 | one-time |
| 阴影面积进阶题库 | $1.99 | one-time |
| 折叠问题题库 | $1.99 | one-time |
| 旋转问题题库 | $1.99 | one-time |
| 中点与中位线题库 | $1.99 | one-time |
| 相似模型题库 | $1.99 | one-time |
| 勾股定理题库 | $1.99 | one-time |
| 江苏真题精选题库 | $1.99 | one-time |
| 经典几何模型题库 | $1.99 | one-time |
| 全解锁买断 | $14.99 | one-time |


## Frequently asked questions

### Is 学习成长21天 free?

学习成长21天 is free to download, with no in-app purchases.

### Is 几何星球 free?

几何星球 is free to download, with in-app purchases available.

### Do 学习成长21天 or 几何星球 have ads?

Neither 学习成长21天 nor 几何星球 shows ads.

### Which is updated more often, 学习成长21天 or 几何星球?

学习成长21天 ships an update weekly, and 几何星球 every 4 days. Most recently, 学习成长21天 was updated on October 25, 2026 and 几何星球 on October 29, 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.*