# 博士兒數理 vs SubFit

The clearest difference is in-app purchases: 博士兒數理 at none against SubFit's 2. SubFit's advantage is update cadence (every 10 days vs every 35 months) and device support. On price and iOS requirement there is nothing between them.

Both are free to download. SubFit sells 2 in-app purchases, starting at $1.99 per month. 博士兒數理 asks for nothing beyond the download.

博士兒數理 ships an update every 35 months, SubFit every 10 days. The most recent releases landed on October 27, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | 博士兒數理 | SubFit |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | — | No |
| Update frequency | Every 35 months | **Every 10 days** |
| Size | 196 MB | 13 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | — | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Chi Hsien Lai](https://appshunter.io/developer/1039759515) | [Cheng-Gang Wang](https://appshunter.io/developer/6790284003) |

## What reviewers say

### 博士兒數理

[App page](https://appshunter.io/ios/app/id6472875333)

**In-app purchases:** none


### SubFit

[App page](https://appshunter.io/ios/app/subfit/id6790284001)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| SubFit Plus 會員 | $1.99 | per month |
| SubFit Pro 會員 | $3.99 | per month |


## Frequently asked questions

### Is 博士兒數理 free?

博士兒數理 is free to download, with no in-app purchases.

### Is SubFit free?

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

### Which is updated more often, 博士兒數理 or SubFit?

博士兒數理 ships an update every 35 months, and SubFit every 10 days. Most recently, 博士兒數理 was updated on October 27, 2026 and SubFit on October 24, 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.*