As a fun way to review basic facts, I play a form of Concentration with my students. I take 40 sheets of paper and write with a marker 20 short questions and their answers, each on a separate sheet of paper. I mix them up and tape them on the wall.
Then I take another 40 sheets of colored paper (so you can’t see through them) and number them one to 40 and tape them over the other sheets of paper. I’ve laminated these sheets of paper, since I re-use them every time we play Concentration.
Students get in groups of five to 15, depending on how many teams you want. Each team takes turns calling out two numbers. I uncover the corresponding sheets of paper and if they reveal a question and its answer, that team gets a point and another turn. If they don’t match, I cover them back up and the next team gets a turn. The team with the most points when all 40 are uncovered wins the game.