# Math Surface vs DuoNiu Write

The clearest difference is in-app purchases: Math Surface at none against DuoNiu Write's 2. DuoNiu Write's advantage is ads (none vs shown) and iOS requirement (17.0 vs 26.2). On price, update cadence and device support there is nothing between them.

Both are free to download. DuoNiu Write sells 2 one-off in-app purchases. Math Surface asks for nothing beyond the download.

Both ship on a similar rhythm, roughly weekly. The most recent releases landed on November 10, 2026 and November 13, 2026 respectively.

## The numbers

| Metric | Math Surface | DuoNiu Write |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | Yes | **No** |
| Update frequency | Weekly | Weekly |
| Size | 10 MB | 131 MB |
| Requires iOS | 26.2 | **17.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [yuya kanbetsunawa](https://appshunter.io/developer/1597026161) | [娟妹 曹](https://appshunter.io/developer/6780705701) |

## What reviewers say

### Math Surface

[App page](https://appshunter.io/ios/app/math-surface/id6774883910)

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

**In-app purchases:** none


### DuoNiu Write

[App page](https://appshunter.io/ios/app/duoniu-write/id6780910815)

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlimited Poem Practice | $0.99 | one-time |
| Unlock All Poetry | $0.99 | one-time |


## Frequently asked questions

### Is Math Surface free?

Math Surface is free to download, with no in-app purchases.

### Is DuoNiu Write free?

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

### Do Math Surface or DuoNiu Write have ads?

Math Surface shows ads; DuoNiu Write does not.

### Which is updated more often, Math Surface or DuoNiu Write?

Math Surface ships an update weekly, and DuoNiu Write weekly. Most recently, Math Surface was updated on November 10, 2026 and DuoNiu Write on November 13, 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.*