# Know Abacus vs World's Key

The clearest difference is rating: Know Abacus at 4.7 against World's Key's 3.8. Know Abacus also leads on review sentiment (96% vs 55%) and iOS requirement (11.0 vs 15.6). World's Key's advantage is in-app purchases (none vs 1) and ads (none vs shown). On price and device support there is nothing between them.

Both are free to download. Know Abacus sells 1 one-off in-app purchase. World's Key asks for nothing beyond the download.

Know Abacus holds the better App Store score, 4.7 against 3.8. Both are backed by a comparable volume of ratings — 67 and 292 respectively. Written reviews point the same way: 96% of Know Abacus's written reviews are positive against 55% of World's Key's.

Know Abacus ships an update every 2 months, World's Key every 8 days. The most recent releases landed on July 6, 2026 and September 29, 2026 respectively.

## The numbers

| Metric | Know Abacus | World's Key |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (67 ratings)](https://appshunter.io/ios/app/know-abacus/id641867438/reviews)** | [3.8 (292 ratings)](https://appshunter.io/ios/app/worlds-key/id1494964110/reviews) |
| Number of ratings | 67 | **292** |
| Positive reviews | **96.4% of reviews** | 54.5% of reviews |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 2 months | **Every 8 days** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 28 MB | 35 MB |
| Requires iOS | **11.0** | 15.6 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Kittipong Mungnirun](https://appshunter.io/developer/488058533) | [Mohammad Bzeih](https://appshunter.io/developer/1494964109) |

## What reviewers say

### Know Abacus

[App page](https://appshunter.io/ios/app/know-abacus/id641867438)

This app teaches children how to use an abacus for various math operations. It covers counting, addition, subtraction, multiplication, and division, helping to develop their mathematical abilities and brain potential. It offers multiple learning modes and customization options.

**Highlights:** Abacus counting, Addition and subtraction (1 & 2 digits), Multiplication and division (1-2 digits), Mental math practice, Review and random lessons, Customizable abacus (color, touch), Multiple languages

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads | $2.99 | one-time |


### World's Key

[App page](https://appshunter.io/ios/app/worlds-key/id1494964110)

This interactive educational app offers audio-visual lessons and exercises for English and Science curricula for Kindergarten and Primary levels. Students can access engaging content and assessments through an online account, supplementing their printed books.

**Highlights:** Interactive audio-visual lessons, English and Science curricula, Kindergarten and Primary levels, Interactive exercises, Assessments for lessons, Online account access

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Know Abacus free?

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

### Is World's Key free?

World's Key is free to download, with no in-app purchases.

### Which has better reviews, Know Abacus or World's Key?

Know Abacus is rated higher. Know Abacus averages 4.7 out of 5 from 67 ratings, while World's Key averages 3.8 from 292 ratings.

### Do Know Abacus or World's Key have ads?

Know Abacus shows ads; World's Key does not.

### Which is updated more often, Know Abacus or World's Key?

Know Abacus ships an update every 2 months, and World's Key every 8 days. Most recently, Know Abacus was updated on July 6, 2026 and World's Key on September 29, 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.*