Sum It Up by Adam Hudson

"Adam has put his skills to worthwhile and inspiring use. Excellent stuff." - Derren Brown
A packet of playing cards is mixed and a spectator freely names any card from within.

Next, a small whiteboard or notepad is introduced and the performer writes down sixteen consecutive numbers, inviting the spectator to select any four.

The four chosen numbers are added together, creating a final total. This generated total is counted to in the packet, locating the one card that occupies that position.

The card arrived at proves to be the very one named by the spectator at the beginning of the routine.