Zuzu Top and the Mentalist

Zuzu Top offers a 12-sided die to one of you, either Chip or Barney. Each of you roll your dice then show the audience what number you rolled. I will close my eyes and turn away. Now add all four numbers together shall we? Zuzu shuffles the deck of cards between his tentacles. He reaches down and holds up the card and scribbles on the ace of spades as the number 34. What is this your number? Oh yeah! The crowd bursts into applause and shears shocked and amazed.