# Goldbach's Conjecture vs Cabri Express Primary

The clearest difference is price: Cabri Express Primary at Free against Goldbach's Conjecture's $0.99. Cabri Express Primary also leads on update cadence (every 2 months vs every 8 months) and device support (4 vs 2). Goldbach's Conjecture's advantage is iOS requirement (12.0 vs 14.0). On ads and in-app purchases there is nothing between them.

Cabri Express Primary is free to download; Goldbach's Conjecture costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Goldbach's Conjecture ships an update every 8 months, Cabri Express Primary every 2 months. Both last shipped on October 3, 2026.

## The numbers

| Metric | Goldbach's Conjecture | Cabri Express Primary |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 8 months | **Every 2 months** |
| Size | 34 MB | 101 MB |
| Requires iOS | **12.0** | 14.0 |
| Devices | iPad, Mac | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 12+ |
| Developer | [Ventura Educational Systems](https://appshunter.io/developer/371324172) | [Cabrilog SAS](https://appshunter.io/developer/1058047739) |

## What reviewers say

### Goldbach's Conjecture

[App page](https://appshunter.io/ios/app/goldbachs-conjecture/id1385243580)

**In-app purchases:** none


### Cabri Express Primary

[App page](https://appshunter.io/ios/app/cabri-express-primary/id1668145657)

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Goldbach's Conjecture free?

Goldbach's Conjecture costs $0.99, with no in-app purchases.

### Is Cabri Express Primary free?

Cabri Express Primary is free to download, with no in-app purchases.

### Do Goldbach's Conjecture or Cabri Express Primary have ads?

Neither Goldbach's Conjecture nor Cabri Express Primary shows ads.

### Which is updated more often, Goldbach's Conjecture or Cabri Express Primary?

Goldbach's Conjecture ships an update every 8 months, and Cabri Express Primary every 2 months. Most recently, Goldbach's Conjecture was updated on October 3, 2026 and Cabri Express Primary on October 3, 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.*