Pair Plus One, also known as TRIO, is a card game for two to four players. It is played with a standard deck of 52 cards and the objective is to be the first player to reach a predetermined score. The game is played by each player being dealt three cards, and then the players take turns playing their cards in pairs or trios. The player with the highest-ranking pair or TRIO wins the round and scores points. The game ends when one player reaches the predetermined score.