SpeedJack 21 vs Counting and Probability
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
SpeedJack 21
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.
- Blackjack basic strategy practice
- Consecutive correct answer challenge
- Server-based time ranking
- Improve casino winning average
- User sign-in required for challenges
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It is an application which helps your blackjack skill. You can practice basic strategy of blackjack with this application. If you succeed 20 times consecutive correct answer, your time record spent will be ranked on the server. Please sign-in before challenge. If you can pass this challenge easily without failing in short time, your winning average at the casino will be increasing.
Counting and Probability
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.
- Math competition problem collection
- Detailed solutions provided
- Bookmark problems for review
- Note-taking for study
- Organized problem collection
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The subject of counting and probability is a challenging in math competitions for math learners. This APP collects the math competition problems on various levels in a organized way and provide solutions to all the problems. The problems can be bookmarked for reviews and notes can be written for the study.
Screenshots
Verdict
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.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
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.
| Parameter | SpeedJack 21 | Counting and Probability |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) | 5.0 (7 ratings) |
| Number of ratings | 1 | 7 — better |
| Update frequency | Fortnightly — better | Every 8 months |
| Ads | Yes | No — better |
| In-app purchases | No | No |
| Monetization | Ad-supported | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 13.0 | 13.0 |
| Further details — not scored | ||
| Size | 86 MB | 8 MB |
| Age rating | 12+ | 4+ |
| Developer | KwangRim Ahn | DEEPPATH LLC |
Customer experience
SpeedJack 21
Counting and Probability
In-app purchases
SpeedJack 21
No in-app purchases
Counting and Probability
No in-app purchases
Questions
Is SpeedJack 21 free?
Is Counting and Probability free?
Which has better reviews, SpeedJack 21 or Counting and Probability?
Do SpeedJack 21 or Counting and Probability have ads?
Which is updated more often, SpeedJack 21 or Counting and Probability?
Other comparisons
