Players may write the same number twice, but no more than twice. A player shuffles the cards and places them facedown in a stack.
Players take turns taking the two top cards from the stack.
If the sum of the numbers is a number on a player's grid, that player places a penny or counter on that number. If there is already a counter on that number, the player places another counter on top of it. If, by the time the cards have all been used, no player has gotten four in a row, then the player with more counters on the grid wins.