War used to be a favourite card game of mine as a kid that I would play with my mom or sister. With the deck split equally in two piles, each of the players would turn over the top card at the same time and the highest card would win the round and keep the cards. The point of the game was to have all the cards eventually.
With a simple twist, I turned this into an engaging math game. When the students turned over their cards at the same time, they had to multiply the values of both cards together and yell out the answer. The first person with the correct answer would win the round and keep the cards.
Worked like a charm! It turned out to be an indoor break time after math due to the Singapore rain and I couldn't get my kids to stop! Easy and fun way to practice your multiplication tables without feeling like you are writing them down over and over again.