Box 2 – Second Presentation

To show the child that the area of all the equilateral triangles is the same.

1. Have the child build the triangles as in the First Presentation.
2. Say: “All these triangles are the same.”
3. Pick up the gray triangle and, starting with the green triangle, place it on top of each of the others.
4. Place directly on top of the others, trace the two triangles from bottom left corner, going counter clockwise, and say: This triangle is the same as this triangle” each time.
5. When each of the triangles have been compared to the first one and traced, bring the gray triangle forward and place it in front of the child.
6. Starting with the green triangle, build all of them on top of the gray one.
7. When finished, trace around all the triangles and say:”All of these triangles are the same size.”
8. Return the triangles to their proper position.
9. Bring the box forward and replace the triangles in the following order:
   1. Gray Triangle
   1. Green Triangle
   1. Yellow Triangle
   1. Red Triangle
10. Close the box, return the materials to the shelf

POINTS OF INTEREST

• Tracing the black lines.
• Matching the triangles.
• Superimposing the gray triangle.
• Making the one big triangle.
• Indirect superimposing when putting them back in the box.
• Naming the shapes and the various triangles used to make them.

CONTROL OF ERROR

• Black guides.
• Different colors of triangles.

DIRECT AIMS

• Showing that different sets of triangles, when put together, are equal in size to the gray triangle.
• Development of the ability to discriminate geometric forms.
• Growth in concentration and independence.

INDIRECT AIMS

• Preparation for Geometry.
• Development of appreciation of line and form.
• Development of creativity.