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Challenge your friends to find out who is best at performing math under time pressure.
Sum it up is a game that challenges the player to do math under time pressure. A target number is shown and the player has to add up the numbers in the grid to meet the target number. When the number is reached it will be added to the player's score. When the time runs out the remaining numbers are add up and subtracted from the player's score and that is the actual score.