A 3rd-6th grade math based card game with minimal and cheap supplies. This game can be used as a rainy day activity or as group activities as a way to introduce or wrap up a topic. All you need: a deck of dollar-store cards per 5 students (6 for a class of 30 for $8 at your dollar store), pencil, paper. The activity can be between 10-20 minutes and encourages social interaction.
While the game is meant for younger students, older students and adults have agreed it is a great way to pass the time.