An impossible location effect!

A card is chosen and then shuffled back into a random position in the deck.

Your spectator takes out their phone and adds up a bunch of random numbers of their choice.

Once the number is passed 1 million they add up the digits to come up with a number. Let's say the random number is 18. Now they count down 18 cards in the deck and somehow the chosen card is there!

Easy to do.

No gimmicks.