# Thirteen Game

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The Thirteen Game is a Nim-style counting game that I originally learned about from Julie Morgan’s lovely blog. It’s the perfect time filler game for the first week of school when schedules can be weird and classes tend to be regularly cut short. I use this game whenever I have a few extra minutes with a class. Students LOVE it!

## Rules of the Thirteen Game

• Arrange the class in a circle. My students usually end up in some sort of irregular polygon. The shape doesn’t really matter. It’s just intended to make it easier to tell which students are still in the game.
• The first person may either start by saying “1”, “1, 2”, or “1, 2, 3.”
• Each subsequent person must say either the next 1, 2, or 3 digits. For example: If the first person said “1, 2” the next person might say “3, 4, 5.”
• Play continues around the circle which the next person always saying either 1, 2, or 3 digits to continue the number sequence.
• The person who ways 13 is out. They must leave the circle.
• Continue playing until there is one overall winner.

## Other Games

If you like quick games like this, Julie Morgan shares several other ideas for games that take almost no time at all! Whenever I have used the thirteen game with students, they always beg to play again. I have even had students organize their own games of thirteen throughout the year when there were a few minutes left in class.

Interested in other counting games like this? The Riverbend Community Math Center has an entire page dedicated to variations on Nim.