# Flash vs 결이 주산

The clearest difference is ads: 결이 주산 at none against Flash's shown. Flash's advantage is update cadence (every 2 months vs every 4 months). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Flash ships an update every 2 months, 결이 주산 every 4 months. The most recent releases landed on November 3, 2026 and November 5, 2026 respectively.

## The numbers

| Metric | Flash | 결이 주산 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | **Every 2 months** | Every 4 months |
| Size | 29 MB | 17 MB |
| Requires iOS | **17.0** | 18.6 |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [yeeun seo](https://appshunter.io/developer/1634215603) | [Jieun Son](https://appshunter.io/developer/1896738610) |

## What reviewers say

### Flash

[App page](https://appshunter.io/ios/app/flash-mental-math/id1634215601)

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

**In-app purchases:** none


### 결이 주산

[App page](https://appshunter.io/ios/app/id6772425301)

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

**In-app purchases:** none


## Frequently asked questions

### Is Flash free?

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

### Is 결이 주산 free?

결이 주산 is free to download, with no in-app purchases.

### Do Flash or 결이 주산 have ads?

Flash shows ads; 결이 주산 does not.

### Which is updated more often, Flash or 결이 주산?

Flash ships an update every 2 months, and 결이 주산 every 4 months. Most recently, Flash was updated on November 3, 2026 and 결이 주산 on November 5, 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.*