Got lots of left-over greeting cards? Here’s one fun way I found to use them with kindergarten and first graders. I sort the cards into two categories and the students try and figure out my rule.

In the example above, I sorted the cards into pumpkins and hearts. It was pretty easy for students to figure that one out. But, after that, they can get pretty tricky and student really need to look carefully for similarities within groups: cats vs other animals; the color purple in the cards vs non-purple; “real” photo vs drawing; the word ‘Halloween’ vs cards without ‘Halloween’ written, etc.

For the students who think they know my rule, I show another card and ask them which group they think it belongs to. We do several more before I have students share what they think my rule is.

Of course, it’s always fun to sort the students into groups, too! I have 4-5 students in each of two sorting groups stand in front of the class while the ones who are seated see if they can figure out my rule. It’s even fun to have students work in pairs to see if they can stump the class by sorting students into groups with their own rules.

This is a good pre-algebra activity. Students need to think logically about the attributes of each group then apply those rules.

CCSS: K.MD.3