# Quick mental calculation vs Goldbach conjecture

The clearest difference is device support: Quick mental calculation at 2 against Goldbach conjecture's —. Quick mental calculation also leads on iOS requirement (12.0 vs 16.0). On price and in-app purchases there is nothing between them.

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

## The numbers

| Metric | Quick mental calculation | Goldbach conjecture |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | Yes | — |
| Update frequency | Every 11 days | — |
| Size | 21 MB | 1 MB |
| Requires iOS | **12.0** | 16.0 |
| Devices | **iPhone, iPod** | — |
| Age rating | 4+ | 4+ |
| Developer | [ERX](https://appshunter.io/developer/513941286) | [Sungjun Kim](https://appshunter.io/developer/1602461985) |

## What reviewers say

### Quick mental calculation

[App page](https://appshunter.io/ios/app/quick-mental-calculation/id841970890)

**Features:** macOS Compatibility

**In-app purchases:** none


### Goldbach conjecture

[App page](https://appshunter.io/ios/app/goldbach-conjecture/id6627338523)

**In-app purchases:** none


## Frequently asked questions

### Is Quick mental calculation free?

Quick mental calculation is free to download, with no in-app purchases.

### Is Goldbach conjecture free?

Goldbach conjecture 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.*