This is a great way to teach number systems to children. The deck of cards (which is divided into suits of 10 cards each, the suits are words, Arabic numerals, Roman numerals, hash marks, and objects) is divided evenly into 2 piles. 2 starter cards are placed face-up in the center, and 4 cards placed in front of each player. Both players work to get rid of their cards by placing them on top of the starter cards in a sequential manner (ie, 2 on 3, 8 on 9, etc...) while keeping 4 cards in front of him at all times. the first player to get rid of his or her cards wins.