You have one, large envelope that contains a prediction, 5 cards individually numbered from 1-5 and one pack of cards. You invite the spectator to shuffle the 5 numbered cards and to choose any two, from the five, that they wish. You then ask them to add the two numbers, from their two chosen cards, together. You then ask the spectator to create a random, 2 digit number by re-arranging the two cards. Whatever number they create, from the re-arranged cards, is then subtracted from the total of the two cards that were chosen. This will leave you with one number.
Lets say, for example, that this number is 11. You then take the deck of cards and deal to the 11th card.
This card matches the prediction in the large envelope - EVERY TIME!