Numberlines is played on a board consisting of 9x9 squares on which the numbers 1 to 9 each occur 9 times. Each player is dealt 4 cards from a deck containing 4 times the numbers 1 to 9, 2 plus cards and 2 minus cards. The goal of Numberlines is to be the first to form 2 continuous rows with 5 squares in the own color.
Taking turns, the players play a card and choose a square with the number corresponding to the played card. If no card can be played, the player must pass by placing all his cards on the discard pile. The opponent then receives 1 more turn, after which his cards are also placed on the discard pile. After this, 4 cards are dealt to both players.
When a minus card is played, the player may take 1 square in the opponent's color from the board, except if it is part of an already placed row of 5. When a plus card is played, the player may choose a square with any number.
The player to first form 2 continuous rows (horizontally, vertically or diagonally) with 5 squares in his own color wins the game. Squares of an already laid row of 5 do not count when forming a new row unless multiple rows are formed in one turn.