# Calculation Triangle vs DfdS

The clearest difference is price: DfdS at Free against Calculation Triangle's $0.99. DfdS also leads on update cadence (every 6 weeks vs every 21 months). Calculation Triangle's advantage is device support (3 vs 1) and iOS requirement (6.0 vs 14.1). On ads and in-app purchases there is nothing between them.

DfdS is free to download; Calculation Triangle costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Calculation Triangle ships an update every 21 months, DfdS every 6 weeks. The most recent releases landed on October 7, 2026 and October 16, 2026 respectively.

## The numbers

| Metric | Calculation Triangle | DfdS |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| Rating | **[3.0 (1 ratings)](https://appshunter.io/ios/app/calculation-triangle/id575736731/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 30.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 21 months | **Every 6 weeks** |
| Monetization | Paid | — |
| Size | 22 MB | 39 MB |
| Requires iOS | **6.0** | 14.1 |
| Devices | **iPhone, iPad, iPod** | iPad |
| Age rating | 4+ | 4+ |
| Developer | [Christian Urff](https://appshunter.io/developer/415894463) | [Elke & Gunter Reimann-Dubbers Stiftung](https://appshunter.io/developer/1451814894) |

## What reviewers say

### Calculation Triangle

[App page](https://appshunter.io/ios/app/calculation-triangle/id575736731)

This virtual manipulative helps develop flexible arithmetic thinking. Users can create puzzles, model problems, and explore number relationships by adding, moving, and hiding tokens within a calculation triangle.

**Highlights:** Virtual calculation triangle manipulative, Token manipulation for arithmetic, Create and solve number puzzles, Hide/show fields and numbers, Shake to clear the triangle, Explore number relationships

**Features:** macOS Compatibility

**In-app purchases:** none


### DfdS

[App page](https://appshunter.io/ios/app/dfds-kita-app-digital-plus/id1451814895)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Calculation Triangle free?

Calculation Triangle costs $0.99, with no in-app purchases.

### Is DfdS free?

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

### Do Calculation Triangle or DfdS have ads?

Neither Calculation Triangle nor DfdS shows ads.

### Which is updated more often, Calculation Triangle or DfdS?

Calculation Triangle ships an update every 21 months, and DfdS every 6 weeks. Most recently, Calculation Triangle was updated on October 7, 2026 and DfdS on October 16, 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.*