# i vs Math Ninjas

The clearest difference is rating: i at 4.2 against Math Ninjas's 3.5. i also leads on update cadence (every 6 days vs every 7 months). Math Ninjas's advantage is ads (none vs shown) and review sentiment (64% vs 43%). On price, ratings volume, in-app purchases and monetization model there is nothing between them.

Both are free to download. i sells 10 one-off in-app purchases and Math Ninjas sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

i holds the better App Store score, 4.2 against 3.5. Both are backed by a comparable volume of ratings — 10 and 6 respectively. Written reviews complicate that: 43% of i's written reviews are positive against 64% of Math Ninjas's, so the app with the better star average is not the one people write more warmly about.

i ships an update every 6 days, Math Ninjas every 7 months. The most recent releases landed on September 22, 2026 and August 12, 2026 respectively.

## The numbers

| Metric | i | Math Ninjas |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.2 (10 ratings)](https://appshunter.io/ios/app/i-memorize-sheet/id803026043/reviews)** | [3.5 (6 ratings)](https://appshunter.io/ios/app/math-ninjas/id895508928/reviews) |
| Number of ratings | **10** | 6 |
| Positive reviews | 42.9% of reviews | **63.6% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 6 days** | Every 7 months |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 67 MB | 198 MB |
| Requires iOS | 18.0 | **13.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [BrainApp LLC](https://appshunter.io/developer/726018559) | [HARASHOW Interactive](https://appshunter.io/developer/356148278) |

## What reviewers say

### i

[App page](https://appshunter.io/ios/app/i-memorize-sheet/id803026043)

This app allows users to hide text in study materials using a filter, mimicking a red sheet for effective memorization. It supports photos and PDFs, enabling studying anytime, anywhere with just a smartphone.

**Highlights:** Hide text with red filter effect, Study photos and PDFs, Add check marks for progress, Efficient study with navigation, Use anytime, anywhere

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| i-Memorize Sheet Remove ADs Option | $0.99 | one-time |
| imc00010 | $0.99 | one-time |
| imc00020 | $0.99 | one-time |
| i-Mem-Contents imc00030 | $0.99 | one-time |
| i-Mem-Contents imc00040 | $0.99 | one-time |
| i-Mem-Contents imc00010 | $0.99 | one-time |
| i-memorize Sheet File-Limit release add-on | $2.99 | one-time |
| i-memorize Sheet PDF page-Limit release add-on | $4.99 | one-time |
| Pro licence(campaign) | $5.99 | one-time |
| i-memorize Sheet Limit release add-on | $6.99 | one-time |


### Math Ninjas

[App page](https://appshunter.io/ios/app/math-ninjas/id895508928)

This educational game uses a ninja theme to make learning mathematics fun for children on iPhone and iPad. Kids can engage with math concepts through interactive gameplay.

**Highlights:** Game-based learning, Mathematics education, Ninja theme, Interactive gameplay, iOS compatible

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Version | $3.99 | one-time |


## Frequently asked questions

### Is i free?

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

### Is Math Ninjas free?

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

### Which has better reviews, i or Math Ninjas?

i is rated higher. i averages 4.2 out of 5 from 10 ratings, while Math Ninjas averages 3.5 from 6 ratings.

### Do i or Math Ninjas have ads?

i shows ads; Math Ninjas does not.

### Which is updated more often, i or Math Ninjas?

i ships an update every 6 days, and Math Ninjas every 7 months. Most recently, i was updated on September 22, 2026 and Math Ninjas on August 12, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*