Styx by Docc Hilford

Docc introduces 4 sticks, each with 4 sides. Along each side is 4 numbers. The spectator arranges the sticks in any orientation and adds up the numbers via a calculator but way before she has finished, Docc has already completed the calculation in his head. He repeats this several more times with increasing difficulty before finally predicting a total of a sum he hasn’t even seen!