Help on this "physic thing"

Question

what is the trick to when someone ask you for a number and then you have it in your head, and then they say divide it by two, then add a number of there choice, divide it by 2 or something, minus the first number you had?

:)

help please

Answer 1

Hello

Don't know, but it isnt anything to do with psychic ability.

Sadhara