Example: Mentalist Trick (2)

(related to Part: Tricks for Mental Maths)

You can use your mentalist power to impress people by guessing the number they have thought:

Finding out the number thought by your partner

Now, pretend to use your "mentalist powers" and without explaining, what you are doing, perform the following calculations:

Think about, why this trick always works. If you have a solution, edit this article correspondingly, or provide a comment.

Thank you to the contributors under CC BY-SA 4.0!