Derision

Derision is a 1 - 2 player math game for the TRS-80.

The player or computer opponent take turns deriving a number. At the start of each round, a target number is selected. The second player must then derive another number from it by halving, doubling, squaring, or taking the square root of a number. In a two-digit number, the player can add, subtract, multiply, or divide its digits. Points are scored by using the target number as one of the digits of the number, or if the digits of the number add, subtract, multiply, or divide to total the target number. In deriving numbers, the players may not use any number twice, nor may not use the target number itself. When no number can be legally derived, the round is over and a new target number is chosen and play begins again. The first player to reach 10 points is the winner.