Effect:
Introducing the Electronic Scientific Calculator (supplied) you explain that, as an experiment, you are asking everyone you meet to name ANY card and ANY number from 1 to 52, then recording their answers on your pocket computer. Let’s assume they name the 8♦ and 23.

You key in their details then say, “The last person I asked said the Q♣ and 48. I then amazed him by doing this… you now pick up a tabled deck and deal down to the 48th card… it’s the Q♣. You assemble the deck then, as an apparent afterthought, as they named the 8♦ and the number 23, ask them deal down to the 23rd card… it’s the 8♦!”