# Arithmus vs Keep R

The clearest difference is ads: Keep R at none against Arithmus's shown. Arithmus's advantage is iOS requirement (15.1 vs 17.0). On price, update cadence, in-app purchases and device support there is nothing between them.

Both are free to download. Arithmus sells 2 in-app purchases, starting at $2.99 per month and Keep R sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

Arithmus ships an update every 9 days, Keep R every 2 weeks. The most recent releases landed on November 5, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | Arithmus | Keep R |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 9 days** | Every 2 weeks |
| Size | 50 MB | 256 MB |
| Requires iOS | **15.1** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Arithmus Team](https://appshunter.io/developer/1872561782) | [boyoung kim](https://appshunter.io/developer/1837090334) |

## What reviewers say

### Arithmus

[App page](https://appshunter.io/ios/app/arithmus-math-brain-training/id6758364464)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium (Monthly) | $2.99 | per month |
| Premium (Yearly) | $29.99 | per year |


### Keep R

[App page](https://appshunter.io/ios/app/keep-r-60s-survival/id6758564645)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Golden Egg | $0.99 | one-time |


## Frequently asked questions

### Is Arithmus free?

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

### Is Keep R free?

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

### Do Arithmus or Keep R have ads?

Arithmus shows ads; Keep R does not.

### Which is updated more often, Arithmus or Keep R?

Arithmus ships an update every 9 days, and Keep R every 2 weeks. Most recently, Arithmus was updated on November 5, 2026 and Keep R on October 28, 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.*