Abstract: A calculator, packaged in a wristwatch-style housing, with wrist strap, is usable by the player of a card game, such as blackjack, in obtaining a game strategy decision or prompt, and contains a keyboard on the wrist housing unit, by which the card game player enters card value and hand designation information. This keyboard drives a display on the wrist housing, and has a microprocessor powered calculator within the housing where the calculator performs the game decision calculations. The results of the calculations drive an output display prompter on the wrist housing to prompt the game player on blackjack decisions.