# StroopEffect2 vs 算数忍者〜九九の巻〜完全版

The clearest difference is review sentiment: StroopEffect2 at 100% against 算数忍者〜九九の巻〜完全版's 0%. StroopEffect2 also leads on price ($2.99 vs $4.99). 算数忍者〜九九の巻〜完全版's advantage is update cadence (every 5 months vs every 14 months) and iOS requirement (11.0 vs 15.6). On ads, in-app purchases and device support there is nothing between them.

StroopEffect2 costs $2.99 and 算数忍者〜九九の巻〜完全版 $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

StroopEffect2 ships an update every 14 months, 算数忍者〜九九の巻〜完全版 every 5 months. The most recent releases landed on September 18, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | StroopEffect2 | 算数忍者〜九九の巻〜完全版 |
| --- | --- | --- |
| Price | **$2.99** | $4.99 |
| Positive reviews | **100.0% of reviews** | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 14 months | **Every 5 months** |
| Monetization | Paid | — |
| Size | 2 MB | 133 MB |
| Requires iOS | 15.6 | **11.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Yasuyoshi Ota](https://appshunter.io/developer/1500357652) | [Fantamstick](https://appshunter.io/developer/563146308) |

## What reviewers say

### StroopEffect2

[App page](https://appshunter.io/ios/app/stroopeffect2/id1050388935)

This app demonstrates the psychological phenomenon known as the Stroop effect. It presents a time-trial game where users must identify the color of words, even when the word itself names a different color. It's a fun way to explore cognitive processing and reaction times.

**Highlights:** Stroop effect demonstration, Time trial game mode, Cognitive processing experiment, Reaction time measurement, Educational psychology tool

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

**In-app purchases:** none


### 算数忍者〜九九の巻〜完全版

[App page](https://appshunter.io/ios/app/id1483173959)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is StroopEffect2 free?

StroopEffect2 costs $2.99, with no in-app purchases.

### Is 算数忍者〜九九の巻〜完全版 free?

算数忍者〜九九の巻〜完全版 costs $4.99, with no in-app purchases.

### Do StroopEffect2 or 算数忍者〜九九の巻〜完全版 have ads?

Neither StroopEffect2 nor 算数忍者〜九九の巻〜完全版 shows ads.

### Which is updated more often, StroopEffect2 or 算数忍者〜九九の巻〜完全版?

StroopEffect2 ships an update every 14 months, and 算数忍者〜九九の巻〜完全版 every 5 months. Most recently, StroopEffect2 was updated on September 18, 2026 and 算数忍者〜九九の巻〜完全版 on September 10, 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.*