# Montessori Constructive triangles Box 2 Presentation

MATERIALS:

Box 2 is a rectangular box which contains the following 14 triangles:

· 2 yellow right angle triangles with black lines on the shorter side containing the right angle.

· 2 green right angle scalene triangles with a black line on the longer side containing the right angle.

· 2 yellow right angle isosceles triangles with the black line on one of the sides containing the right angle.

· 2 yellow equilateral triangles with the black line on one side.

· 2 grey right angle scalene triangles with the black line opposite the right angle,

· 2 green right angle isosceles triangles with the black line opposite the right angle.

· 1 red right angle scalene triangle with the black line on the longer side containing the right angle.

· 1 red obtuse angle scalene triangles with the black line opposite the obtuse angle.

OBJECTIVES:

To give the child the opportunity to experiment with various geometric shapes.

To discover, at a sensorial level, the various ways these shapes can be divided and combined to form other shapes.

For later work in Maths and Geometry.

CONTROL OF ERROR:

The black lines.

visual

AGE:

4 – 4 ½ years approx.

PRESENTATION:

Individual exercise done at a table or on a floor mat.

Remove the triangles from the box, one at a time. Place the box in the corner of the table with the lid underneath the box. Select one of the triangles. Hold it flat on the table with your left hand.

Trace along the black lines with the middle and index fingers. Look around for the matching triangle. Once found, trace along the black lines again, using the middle and index fingers. Fit the two triangles together by sliding them together on the mat so that their black lines match and so that a new shape is formed. Place this shape to one side and continue in this way with the remaining triangles. Invite the child to try the exercise.

When finished, show the child how to return the triangles to the box carefully.

PRESENTATION 2:

Give a three period lesson on the names of the various triangles.