# 注意力四维训练 vs 学习成长21天

The clearest difference is in-app purchases: 学习成长21天 at none against 注意力四维训练's 3. 学习成长21天 also leads on device support and iOS requirement (9.0 vs 12.0). On price there is nothing between them.

Both are free to download. 注意力四维训练 sells 3 in-app purchases, starting at $0.99 per month. 学习成长21天 asks for nothing beyond the download.

## The numbers

| Metric | 注意力四维训练 | 学习成长21天 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | — | No |
| Update frequency | — | Weekly |
| Size | 22 MB | 66 MB |
| Requires iOS | 12.0 | **9.0** |
| Devices | — | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [晓华 崔](https://appshunter.io/developer/1497841751) | [Guangdong Youyixue Education Technology Co., Ltd.](https://appshunter.io/developer/1508981243) |

## What reviewers say

### 注意力四维训练

[App page](https://appshunter.io/ios/app/id1497842313)

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 月付vip | $0.99 | per month |
| 年卡vip | $6.99 | per year |
| 永久vip权限 | $3.99 | one-time |


### 学习成长21天

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

**In-app purchases:** none


## Frequently asked questions

### Is 注意力四维训练 free?

注意力四维训练 is free to download, with in-app purchases available.

### Is 学习成长21天 free?

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

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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.*