Comparison

dnCalc vs Sliding Puzzle

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

Head to head
About

dnCalc

Perform amazing mathematical "experiences" to impress friends and colleagues. This app allows you to reveal secret numbers, ages, zodiac signs, and more, all without touching a calculator. It's easy to use, requires no memorization, and can be done with your eyes closed.

Highlights
  • Reveal secret numbers
  • Peek at ages and zodiac signs
  • Calculate birth day of week
  • Create custom formulas
  • Works offline
  • Up to 5 participants
Features
Read full description

Imagine... You are enjoying a lunch with friends and you suggest to perform a strange mathematical "experience". You ask for several volunteers to think of a special number, a birthday, the age of their best friend... You then ask them to multiply these numbers together, without you being able to see anything, then multiply the result by a special number that you previously wrote on a piece of paper, before the demonstration begins. Your friends give you orally the final result of these operations. You close your eyes and after a few seconds you reveal in the right order, the secret numbers of your friends! dnCalc will allow you to easily produce this little miracle that you can adapt according to your wishes and to he context. Your friends or colleagues will be asking what magical mathematical operation you mentally do to "extract" their numbers. Guaranteed to impress! • Very easy to do. A PDF document explains in details the procedure (which you can adapt). • Nothing to memorize. • Up to 5 people can be involved in the demonstration. • The spectators manipulate the calculator, you do not touch anything. • You can do this demonstration with your eyes closed. • No need for internet connection. • The trick is absolutely undetectable, nothing to find. • The effect is reproducible several times in a row. Many other cool features : • Force any number you need. • Compute and peek the age of your volunteer. • Compute and peek his zodiac signs (classic or Chinese). • Compute and peek his birth day of week. • Build your own forcing/peeking formulas! *** IMPORTANT *** If you have questions, do not ask them in the app's reviews, in order to preserve the secret. Send an email to dnCalc@moult.org. Thank you ! Alistair Crompton

About

Sliding Puzzle

Read full description

It is a traditional puzzle. Simple, slide the block outside the screen.

Screenshots

dnCalc1 screens
Sliding Puzzle3 screens

Verdict

The call

The clearest difference is price: dnCalc at Free against Sliding Puzzle's $1.99. dnCalc also leads on ads (none vs shown) and update cadence (fortnightly vs every 7 months). On in-app purchases and device support there is nothing between them.

Scored on Price Ā· Rating Ā· Positive reviews Ā· Number of ratings Ā· Update frequency Ā· Ads Ā· In-app purchases Ā· Monetization Ā· Best chart rank Ā· Devices Ā· Requires iOS

CostPrice Ā· In-app purchases Ā· Ads Ā· Monetization

dnCalc is free to download; Sliding Puzzle costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

dnCalc ships an update fortnightly, Sliding Puzzle every 7 months. The most recent releases landed on October 13, 2026 and October 31, 2026 respectively.

Scorecard4 real differences Ā· 4 level
dnCalc versus Sliding Puzzle: the parameters behind the verdict, then further details
ParameterdnCalcSliding Puzzle
PriceFree — better$1.99
Positive reviews100.0% of reviews—
Update frequencyFortnightly — betterEvery 7 months
AdsNo — betterYes
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS11.0 — better16.6
Further details — not scored
Size15 MB91 MB
Age rating4+4+
DeveloperDevious-MonkeyOscar Tsang

In-app purchases

None

dnCalc

No in-app purchases

None

Sliding Puzzle

No in-app purchases

Questions

Is dnCalc free?
dnCalc is free to download, with no in-app purchases.
Is Sliding Puzzle free?
Sliding Puzzle costs $1.99, with no in-app purchases.
Do dnCalc or Sliding Puzzle have ads?
Sliding Puzzle shows ads; dnCalc does not.
Which is updated more often, dnCalc or Sliding Puzzle?
dnCalc ships an update fortnightly, and Sliding Puzzle every 7 months. Most recently, dnCalc was updated on October 13, 2026 and Sliding Puzzle on October 31, 2026.

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