# Mental Calculation & Abacus vs The FOUR

The clearest difference is ads: The FOUR at none against Mental Calculation & Abacus's shown. The FOUR also leads on update cadence (every 3 weeks vs every 6 months). Mental Calculation & Abacus's advantage is iOS requirement (12.0 vs 14.0). On price, in-app purchases and device support there is nothing between them.

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

Mental Calculation & Abacus ships an update every 6 months, The FOUR every 3 weeks. The most recent releases landed on November 11, 2026 and November 4, 2026 respectively.

## The numbers

| Metric | Mental Calculation & Abacus | The FOUR |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (4 ratings)](https://appshunter.io/ios/app/mental-calculation-and-abacus/id1582407909/reviews)** | — |
| Number of ratings | **4** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 6 months | **Every 3 weeks** |
| Monetization | Ad-supported | — |
| Size | 143 MB | 219 MB |
| Requires iOS | **12.0** | 14.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Park Jisang](https://appshunter.io/developer/995438886) | [Korea Campus Crusade for Christ](https://appshunter.io/developer/434814361) |

## What reviewers say

### Mental Calculation & Abacus

[App page](https://appshunter.io/ios/app/mental-calculation-and-abacus/id1582407909)

Engage in a fun and educational game designed to enhance mental calculation skills. Learn to use an abacus with an easy-to-follow tutorial and practice with diverse question types.

**Highlights:** Mental calculation practice, Abacus learning tutorial, Variety of practice questions, Suitable for all ages

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

**In-app purchases:** none


### The FOUR

[App page](https://appshunter.io/ios/app/the-four-grid/id6737247213)

**In-app purchases:** none


## Frequently asked questions

### Is Mental Calculation & Abacus free?

Mental Calculation & Abacus is free to download, with no in-app purchases.

### Is The FOUR free?

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

### Do Mental Calculation & Abacus or The FOUR have ads?

Mental Calculation & Abacus shows ads; The FOUR does not.

### Which is updated more often, Mental Calculation & Abacus or The FOUR?

Mental Calculation & Abacus ships an update every 6 months, and The FOUR every 3 weeks. Most recently, Mental Calculation & Abacus was updated on November 11, 2026 and The FOUR on November 4, 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.*