This PDF should be printed on card stock, or laminated. Estimate printing about 1 to 2 pages per student. In my class we call this game 'War', but call it it whatever you want! Basically it is played in pairs, where each kid has about 10 cards that are face down. On the count of three both players flip over a card, the first one to add both cards' numbers gets to keep both cards, the player with all the cards at the end wins. As they become more advanced I change the rules and they they have to add 4 numbers (cards). I use this activity as a student run task when I am working with a group. If your school is heavy on grading you can have them write out the addition sentence that they make so that you have something to grade. Have fun teaching!