Odd One Out is a math game that helps students work on problem solving strategies. The way it works is that you set up 3 rows of chips. The top row has 3 chips. The middle row has 5 chips. The bottom row has 7 chips. The way you play the game is to take as many chips as you want from each row. The object of the game is to remove the last chip. Students work at identifying strategies to win.
Notice that I used different colored chips. This is best used when first showing the game. Have students make predictions on what they will have to do. The colors don't matter, but they mention them in their predictions.
I have the students record their moves. This helps them come up with strategies for future games. I also have my students journal things like explications on how this is math as well as their strategies for the future.