Set

How it works

Set is a card game. Set cards have 4 features, and for each feature there are 3 possibilities:

  • Color: Green, purple, or red
  • Shape: Diamond, oval, or squiggle
  • Number: 1 shape, 2 shapes, or 3 shapes
  • Shading: Empty, striped, or solid

A group of 3 cards is a set if for each feature the 3 cards are either all the same or all different. For example, the 3 cards shown above are a set because they are all different colors, all different shapes, all the same number, and all the same shading. If instead the 3rd card had squiggles instead of diamonds, it would not be a set, because there would be 2 squiggles and 1 oval, so they wouldn't all have the same shape, but they also wouldn't have all different shapes.

(Note: While cards in a full Set deck have the 4 features described above, we typically simplify things a bit at the start by using only cards that have solid shading, so each card effectively has 3 features rather than 4.)

In this activity, students first play a cooperative game: Each player receives some cards, and then two players play cards; after two cards have been played, all the players search their hands for a third card that can go with the two cards that have been played to make a set. The players repeat this process until there are no cards left or until it's not possible to take any more sets with the remaining cards. Students also try to make set magic squares: they try to arrange the 9 cards with 1 shape and solid shading into a 3 x 3 grid where every row, column, and diagonal makes a set.

Why we like this activity

  • It’s fun! Students enjoy making sets.

  • It helps students develop logical reasoning.

  • It requires students to engage in mathematical habits of mind:

    • Using logic to determine whether a group of 3 cards does or doesn't make a set

    • Finding and using strategies to make a magic square

  • It has a low floor and a high ceiling: Students can start making sets without too much difficulty, but there's a lot more to explore and discover.

 

This activity is based on a game called SET® that is manufactured by PlayMonster.