Described in the book Calculate!, Target Number is a game where players are using math operations trying to get the calculator to display a number in the range of 10 to 20. The game is played on a track that is a large loop. Each player uses the numbers on the track in order. For example, if the calculator displayed 196 and the next number was 512, followed by 70 one could add 512 to number giving 708 and then divide by 70 which would give 10.1142... This number is in the range and would score points for the player who would then pass the calculator to the next player who would continue on the track. Play ends when all the numbers in the loop are have been used.