This interactive activity allows students to practice their addition facts with a sum of 10 or less. The students are divided into pairs to play Think-Tac-Toe. Before the activity, copy the game card pages onto card stock using a different color for each partner. Give each pair a set of game cards (face down). The partner that is selected to go first will pick a card from their stack of cards. They will solve the addition problem aloud. If the other partner agrees that the sum is correct, then the student may use that card to mark their spot on the game board. (The different colors are used as “x” and “o” in the traditional game of tic tac toe.) The first person to get three in a row wins the game! My students have enjoyed practicing their addition facts with this activity during math centers.