# SpeedJack 21 vs Counting and Probability

The clearest difference is ads: Counting and Probability at none against SpeedJack 21's shown. Counting and Probability also leads on monetization model (free vs ad-supported) and ratings volume (7 vs 1). SpeedJack 21's advantage is update cadence (fortnightly vs every 8 months). On price, rating, 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.

On the App Store both sit at effectively the same score — 5.0 for SpeedJack 21 against 5.0 for Counting and Probability. That said, the two scores are not equally well evidenced: Counting and Probability has 7 ratings behind it against 1, so its average is the more settled of the two.

SpeedJack 21 ships an update fortnightly, Counting and Probability every 8 months. The most recent releases landed on June 4, 2026 and June 1, 2026 respectively.

## The numbers

| Metric | SpeedJack 21 | Counting and Probability |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/speedjack-21/id1511287771/reviews) | [5.0 (7 ratings)](https://appshunter.io/ios/app/counting-and-probability/id6444738269/reviews) |
| Number of ratings | 1 | **7** |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | **Fortnightly** | Every 8 months |
| Monetization | Ad-supported | **Free** |
| Size | 86 MB | 8 MB |
| Requires iOS | 13.0 | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 12+ | 4+ |
| Developer | [KwangRim Ahn](https://appshunter.io/developer/1511287770) | [DEEPPATH LLC](https://appshunter.io/developer/1531915855) |

## What reviewers say

### SpeedJack 21

[App page](https://appshunter.io/ios/app/speedjack-21/id1511287771)

Practice your blackjack basic strategy with this educational app. Achieve consecutive correct answers to rank your time record on the server and improve your casino winning average.

**Highlights:** Blackjack basic strategy practice, Consecutive correct answer challenge, Server-based time ranking, Improve casino winning average, User sign-in required for challenges

**Features:** macOS Compatibility

**In-app purchases:** none


### Counting and Probability

[App page](https://appshunter.io/ios/app/counting-and-probability/id6444738269)

Access a curated collection of math competition problems focused on counting and probability. This app provides detailed solutions, bookmarking features for review, and note-taking capabilities to aid your study.

**Highlights:** Math competition problem collection, Detailed solutions provided, Bookmark problems for review, Note-taking for study, Organized problem collection

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is SpeedJack 21 free?

SpeedJack 21 is free to download, with no in-app purchases.

### Is Counting and Probability free?

Counting and Probability is free to download, with no in-app purchases.

### Which has better reviews, SpeedJack 21 or Counting and Probability?

SpeedJack 21 and Counting and Probability are both rated 5.0 out of 5 on the App Store, from 1 and 7 ratings respectively.

### Do SpeedJack 21 or Counting and Probability have ads?

SpeedJack 21 shows ads; Counting and Probability does not.

### Which is updated more often, SpeedJack 21 or Counting and Probability?

SpeedJack 21 ships an update fortnightly, and Counting and Probability every 8 months. Most recently, SpeedJack 21 was updated on June 4, 2026 and Counting and Probability on June 1, 2026.

---

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