Math Background

Lesson: Identify, Sort, Classify
Developing the Concept

Once the children have had several opportunities to sort objects with one attribute, it's time to try sorting with more than one attribute and to try finding objects that don't belong to a group. Gather the children in a circle.

Materials: large red squares and red and yellow triangles, fruit and vegetable cards

Preparation: Cut out large red squares and red and yellow triangles from construction paper. Have ready two large circles of yarn. Prepare cards with round fruits and vegetables on them, such as grapefruit, oranges, grapes, melons, potatoes, onions. Also include cards with carrots and bananas.

  • Ask: Can you put all the red shapes in one of the yarn circles? Now put the triangles in the other yarn circle.
  • Allow time for children to follow your request. Talk about how the shapes in the yarn circles are the same and how they are different. Then lead children to see that there is a bit of a problem here—there are some triangles in with the squares so they cannot put all the triangles in the other yarn circle.
  • Ask: What can we do now?
  • Allow time for discussion of ideas. Finally, elicit from children that they can overlap the yarn circles and put the red triangles in the common part. Then all the squares are in one section, all the triangles are in the other section, and the red triangles are in the common section because they are both red and triangles. Point out that sometimes things can be sorted in more than one way.
  • Next have children try playing Which One Doesn't Belong? Lay out four cards — a melon, a grape, an orange, and an onion.
  • Say: Look at the cards that I have laid out.
  • Ask: Which card doesn't belong? Why doesn't it belong?
    Children should say the onion because it is a vegetable.
  • Say: Now I am going to change the cards.
    Pick up all the cards and lay out the orange, grapefruit, melon, and banana.
  • Ask: Which card doesn't belong? Why doesn't it belong?
    Children should say the banana because it isn't round.
  • Continue to play, letting children sort the cards into different groupings.

Wrap-Up and Assessment Hints
Children love to sort and group objects. As you summarize, remind children that there are many ways to sort things, but that they should have a reason for sorting as they do. Give children more difficult sorts only as they are ready.

Houghton Mifflin Math Grade K