The game uses a Mirror Deck, which means that each card has a 2-digit number on it and when you rotate the card 180° the digits swap places. For example, the card with 27 shows a 72 from the other direction. Every number from 01 to 98 is in the deck.

This means every time you play a card, you see one number, but your opponent sees the mirrored number, giving you each different options as the game progresses.