App 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.

*** IMPORTANT ***
If you have questions, do not ask them in the app's reviews, in order to preserve the secret.
Send an email to [email protected]

Thank you !
Alistair Crompton

iPhone Screenshots

(click to enlarge)

dnCalc screenshot 1 dnCalc screenshot 2

App Changes

  • November 14, 2017 Initial release

Other Apps From Sebastien Raupp

Dumb Blocks Stack Master