# Mental Arithmetic Helper vs MIRAIRO Door

The clearest difference is ads: MIRAIRO Door at none against Mental Arithmetic Helper's shown. On price, update cadence, 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 Arithmetic Helper ships an update fortnightly, MIRAIRO Door every 4 weeks. The most recent releases landed on October 30, 2026 and November 4, 2026 respectively.

## The numbers

| Metric | Mental Arithmetic Helper | MIRAIRO Door |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | **Fortnightly** | Every 4 weeks |
| Size | 37 MB | 2 MB |
| Requires iOS | 15.8.3 | **15.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Hideaki Uchikoshi](https://appshunter.io/developer/1559575002) | [Haudi, Inc.](https://appshunter.io/developer/1694190484) |

## What reviewers say

### Mental Arithmetic Helper

[App page](https://appshunter.io/ios/app/mental-arithmetic-helper/id6502036493)

**Features:** macOS Compatibility

**In-app purchases:** none


### MIRAIRO Door

[App page](https://appshunter.io/ios/app/mirairo-door/id6738896340)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Mental Arithmetic Helper free?

Mental Arithmetic Helper is free to download, with no in-app purchases.

### Is MIRAIRO Door free?

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

### Do Mental Arithmetic Helper or MIRAIRO Door have ads?

Mental Arithmetic Helper shows ads; MIRAIRO Door does not.

### Which is updated more often, Mental Arithmetic Helper or MIRAIRO Door?

Mental Arithmetic Helper ships an update fortnightly, and MIRAIRO Door every 4 weeks. Most recently, Mental Arithmetic Helper was updated on October 30, 2026 and MIRAIRO Door 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.*