A little easy trick that will impress everyone.
The magician gives a dice and a small can with a lid to a spectator who has the task of putting the dice into the box with a random side upwards and put the lid on. Meanwhile, the magician turns his back so he does not have a chance to see the spectator's choice. The little can with the dice is then sealed inside a second larger can. The magician then holds it against his forehead and after a moment of thought, he is capable of telling exactly how many dots are on the dice!