Hexa: Derwin Playing Cards with Hexadecimal Power (base 16). This is a modified standard deck of cards using base 16. There are 64 cards in the deck in four suits, plus two jesters. It includes rules for several traditional card game variants, including poker, rummy, bridge, old maid, cribbage, blackjack and more. Among the blurbs on the package: 'Educational & Entertaining' 'Challenge your Math Skills' 'May be used with a Scientific Calculator'. - BoardGameGeek