Comparison

Zetamac Arithmetic Practice vs 21 Sharp

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Zetamac Arithmetic Practice

This app offers mental math practice tailored for quantitative finance professionals. It focuses on improving calculation speed and accuracy for complex numerical problems.

Highlights
  • Mental math practice
  • Quantitative finance focus
  • Calculation speed improvement
  • Accuracy enhancement
  • Numerical problem solving
Features
Read full description

Zetamac - A mental math practice app used in the Quantitative Finance world.

About

21 Sharp

Master blackjack strategy and card counting with this professional-grade trainer. Learn optimal plays, practice counting systems, and track your progress with realistic simulations and reference guides. Reduce the house edge and gain a competitive advantage.

Highlights
  • Basic strategy training
  • Card counting drills (Hi-Lo)
  • Realistic practice table
  • Reference guides
  • Progress tracking and achievements
Features
Read full description

Turn the odds in your favor. 21 Sharp is a professional-grade blackjack trainer that teaches you basic strategy and card counting—the same techniques used by advantage players to beat the house. BASIC STRATEGY TRAINING Learn the mathematically optimal play for every possible hand. Our quiz system drills you on 270+ hand combinations until perfect strategy becomes second nature. Reduce the house edge to just 0.5%. CARD COUNTING DRILLS Master the Hi-Lo counting system with speed-building exercises. Track running counts, calculate true counts, and learn when to increase your bets. Practice until you can count down a full shoe with accuracy. PRACTICE TABLE Play realistic blackjack hands with real-time strategy hints. See the running count, get recommendations for every decision, and learn from your mistakes without risking real money. REFERENCE GUIDES Access complete basic strategy charts and a comprehensive Hi-Lo counting guide anytime. Perfect for quick review before hitting the casino. TRACK YOUR PROGRESS Unlock 25+ achievements as you improve. Monitor your accuracy, streaks, and stats across all training modes. Watch yourself transform from beginner to sharp. Whether you're preparing for Vegas, want to impress at home games, or just love the math behind the game, 21 Sharp gives you the edge. Play Sharp. Win Sharp.

Screenshots

Zetamac Arithmetic Practice4 screens
21 Sharp4 screens

Verdict

The call

The clearest difference is in-app purchases: Zetamac Arithmetic Practice at none against 21 Sharp's 1. Zetamac Arithmetic Practice also leads on ratings volume (18 vs 1). 21 Sharp's advantage is rating (5.0 vs 4.7). On price, ads, device support and iOS requirement 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. 21 Sharp sells 1 one-off in-app purchase. Zetamac Arithmetic Practice asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

21 Sharp holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Zetamac Arithmetic Practice has 18 ratings behind it against 1, so its average is the more settled of the two.

Scorecard4 real differences · 6 level
Zetamac Arithmetic Practice versus 21 Sharp: the parameters behind the verdict, then further details
ParameterZetamac Arithmetic Practice21 Sharp
PriceFreeFree
Rating4.7 (18 ratings)5.0 (1 ratings) — better
Positive reviews83.3% of reviews—
Number of ratings18 — better1
Update frequencyDaily—
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.517.0 — better
Further details — not scored
Size1 MB1 MB
Age rating4+12+
DeveloperJoseph Mabusyslacker llc

Customer experience

Zetamac Arithmetic Practice

All ratings18 ratings
Positive94.4%
Neutral0.0%
Negative5.6%
Written reviews18 reviews
Positive83.3%
Neutral16.7%
Negative0.0%

21 Sharp

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Zetamac Arithmetic Practice

No in-app purchases

1 purchases

21 Sharp

One-time1
  • 21 Sharp Premium$2.99

Questions

Is Zetamac Arithmetic Practice free?
Zetamac Arithmetic Practice is free to download, with no in-app purchases.
Is 21 Sharp free?
21 Sharp is free to download, with in-app purchases available.
Which has better reviews, Zetamac Arithmetic Practice or 21 Sharp?
21 Sharp is rated higher. Zetamac Arithmetic Practice averages 4.7 out of 5 from 18 ratings, while 21 Sharp averages 5.0 from 1 ratings.
Do Zetamac Arithmetic Practice or 21 Sharp have ads?
Neither Zetamac Arithmetic Practice nor 21 Sharp shows ads.

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