According to dominorules.com, 42 is also known as Texas Forty-Two, Four-Hand Texas, and Domino Rounce, Forty-Two is an adaptation of Auction Pitch. It was invented by W. A. Thomas during his boyhood in Garner, Parker County, Texas, about 1885; then it spread throughout the southwestern United States.
In this game, a team of 2 players attempts to win all of the 7 tricks played (1 point per trick) and each of the 5-count dominoes (2 tiles worth 10 points each and 3 tiles worth 5 points each, for a total of 35 points) in the course of one hand, giving the team a total of 42 points (7 + 35 = 42). Thus, the name of the game.

Object of the game: To be the first team to reach 250 points or win 7 hands.