Early on in the year I like to introduce the card games "War" and "Double War." In the Investigations In Number, Data, and Space curriculum (Dale Seymour Publications, 1995) these games are taught to first and second graders as "Compare" and "Double Compare." I used to use this terminology, but the kids all recognized the game as one they'd learned at home as "War," so now I just go with their name for it.
You probably learned to play "War" yourself as a child, but in case you've forgotten... The deck of cards in dealt out evenly between two (or three) players. Each player slaps a card down and the player who's card is the greatest number collects all the cards. If there is a tie, the players have a "war," slapping down three cards upside down and one card facing up. Again, the player with the highest card takes all.
"Double War" is a great adaptation for older students. This time around, instead of slapping down one card only, each player slaps down two cards, adds the cards, and totals are compared. The player whose cards total the greatest number takes all cards.
To simplify things a bit, I have removed all the face cards from the decks used in my classroom. This helps with some of the other card games we play as well.
As the year goes on, these games serve as great filler activities and regular opportunities to practice math fact fluency. Often I ask students to play a card game like this with a partner as they arrive in the morning because students can usually play without a lot of teacher monitoring. On this first introduction, however, I am sure to circulate around the room, observing carefully how students approach the task. Some students will need to count the pictures on the cards in order to compare the numbers, while others will quickly recognize totals. It is possible to learn a lot about students' mathematical understandings by observing them at play.
