Early Math Counts

• A mat, divided in half with a clear line (line of symmetry) distinguishing the divider

• Pattern blocks

• Pictures of symmetrical pattern blocks

Note: Small parts pose a choking hazard and are not appropriate for children age five or under. Be sure to choose lesson materials that meet safety requirements.

1. Show the pattern block symmetry pictures to the children. Ask them what they notice about the pictures. Fold the pictures down the line of symmetry and again ask the children what they notice about the pictures.
2. Explain the concept of symmetry to the children (the two sides of the whole are exactly like one another) and explain that today they are going to use pattern blocks to play The Symmetry Game.

1. Demonstrate how to play the game, which is played in pairs, and choose a child to play the game with you.
2. Give the partners one mat. The first player puts down one pattern block. The pattern block should touch the line of symmetry. The second player copies by placing the same block in the same place, but on the other side of the line of symmetry.
3. Continue the game until both players have used five or six blocks apiece. Point out that the designs they have made are symmetrical. Explain that the design is symmetrical because each side of the line has blocks of the same color in the same place.
4. Remove the blocks and repeat the game. This time, the second player starts the game.

Additional Extensions

• Point out real things in your classroom that are symmetrical. Show them to the children and ask: “Is this (object) symmetrical? Why or why not?”

• Create simple symmetrical pictures, as well as some pictures that are not symmetrical. Ask: “Which of these pictures are symmetrical and which of these pictures are not?” Have the children explain their thinking.

• Symmetrical: The two sides of the whole are exactly like one another (e.g.,”Is the tiger’s face exactly the same on this side of our invisible line as it is on the other side of our line? If so, the tiger’s face is symmetrical.”)
• Same: Identical in kind or quantity (e.g.,”The design is symmetrical because each side of the line has blocks of the same color and in the same place.”)
• Line of Symmetry: Divides an object or design in half, so that both sides are the same (e.g.,”The second player copies by placing the same block in the same place, but on the other side of the line of symmetry.”)

Early Math Glossary

Adapt Lesson for Toddlers

Toddlers may:

• Need some assistance in recognizing the various details of their photos, so that they can better duplicate those details in their mirrored drawings
• Need to see some additional examples of symmetry

Child care providers may:

• Start the game with two pattern blocks and increase the blocks as the children’s understanding of symmetry grows
• Help point out the symmetrical objects within the photo. “You have an eye on this side of your face. Will you need an eye on the other side of your face? Where should that eye go?”
• Continue to point out the symmetry in objects around the room or in books

Adapt Lesson for Preschoolers

Preschoolers may:

• Grasp the concept of symmetry and look for additional ways to extend their knowledge

Child care providers may:

• Have the children go on a “symmetry hunt” around the room, identify symmetrical objects and draw these objects in a notebook. Children should have a math journal readily available to record their mathematical thinking, reasoning and observations. Share their findings. Make a classroom chart of symmetrical objects in the room.