Trick anyone into thinking that you predicted the calculators output. Well the idea behind this trick is that you're not really predicting the outcome but rather forcing it. Sounds cool right?

Example Scenario:
1. Register a number by long pressing the '+/-' button. (Tip: The higher the better)
2. Ask the subject to type in his/her birth year then multiply by a number between 5000-10000 then add some long number (eg: phone num).
3. Tell him/her to press the '=' button.
4. Your registered number will appear!

(Note: There's no limit to what expression you would instruct your subject. The idea here is to make an expression that will yield large number eg: billion)

In case your subject suspects that your app is not yielding the right result you can set the app to normal mode by long pressing the '=' button.

*Bonus Feature
- Auto saving of expression (after pressing '=' button)
- Show recorded expression by clicking '+/-' 7 times
- Clear records by long pressing 'C' button

Credits
Icon made by http://www.flaticon.com/authors/madebyoliver from www.flaticon.com
Icon made by http://www.flaticon.com/authors/freepik from www.flaticon.com

Keywords
magic calculator magic prank trick