Shuffle the cards and deal them out to each player, who keeps their cards face up and puts the cards in numerical order. If a number is missing, it's fine to skip that number and continue with the next available one. See how many number lines each player can create, and how quickly. The winner can be the player who puts all their numbers in order, or the player with the longest number line. For older players, you can require that the number lines match suits--hearts, spades, diamonds or clubs. This game helps reinforce number recognition, counting and number lines. It can also encourage learning about skip counting and missing numbers.
Matching games can be played by any age. Lay out the entire deck face down on a table. Take turns flipping two cards over, trying to get a match. The player with the most matches wins. Number recognition and memory skills are improved by playing this game.
Children who are beginning to add or multiply can play a game similar to War. Deal the deck equally among all players. Each player turns over two cards. Each player will add or multiply their cards and announce the answer. The highest number wins all cards played. In the event of a tie, players will draw two more cards and the highest result wins all cards played. The winner is the player with the most cards when all cards have been played. The game helps improve mental math skills.
In this game, one player is the dealer. The other players have paper and pencils. The dealer deals cards, starting with just two. Each player writes down the numbers on the cards and adds or multiplies them. Depending on the ages and skills of the players, the dealer increases the number of cards dealt each hand. With older kids, you may start the game by dealing four cards. When kids begin to be frustrated with the number of cards, start laying down fewer cards again. This game will improve computations with strings of numbers.
This game also requires paper and pencils, in addition to the cards. Begin the game by dealing three cards in the middle of the playing area. Each player must look at the cards and figure out a way to use all of them to make the largest possible number, and the smallest possible number. Increase the number of cards dealt with each hand. Another variation is to announce a specific number when the cards are dealt. For instance, announce that the winner of the hand is the player that can get closest to the number 20. Deal four cards and let the players use their math skills to create a calculation that is close (or equal) to 20. This game helps build mental math skills, estimation, addition, multiplication, subtraction and division.