Recommended Age: 4 years and onwards
Level of Parent Involvement: Medium during the initial presentation then low once the child has been shown and can work independently. The adult must also make the materials prior to the presentation.
Prerequisites
The child must have worked with the first 3 sets of constructive triangles and should be able to name the shapes formed by the triangles (If the child does not know the names of the shapes they may still work with the second box, ensure you are naming the shapes each time the child works with the second box and continue 3 period lessons with the names of shapes from the geometry cabinet)
Materials
- Set #4 Hexagonal large box PDF Constructive Triangles
- Scissors
- Laminator
- Laminating sheets
- Small tray or box to keep the constructive triangles
- A mat for the child to work on (you may use a towel if you don’t have a work mat OR small carpet mats are available from most carpet stores which are perfect work mats for children doing Montessori exercises from home)
Preparation
- Cut out triangles
- Laminate triangles then trim around the plastic laminating sheet
- Place the triangles in the tray/basket
Steps
- Invite the child letting them know that you are going to show them the fourth constructive triangle set
- Let the child know they need their work mat, once the child has placed their mat they may bring the tray/basket of triangles to the mat
- Sit to the right of the child and begin taking the shapes from the tray/box, the child may help
- The child may put the ones which are the same colour in a pile
- Ask the child “do you think all of these triangles are the same?”
- Stack all triangles on top of each other to show the child that they are the same size
- Unstack the pile and let the child sort the triangles back into their respective colours
- Take the 2 red obtuse angled isosceles triangles, slide together making the black lines touch, saying to the child “you’ve seen this shape before, what is it called?” (child should say rhombus)
- Set aside to the left of the mat
- Form a parallelogram with the grey obtuse angled isosceles and repeat as above, set aside
- Repeat with 3 of the yellow obtuse angled isosceles triangles with 2 black, forming an equilateral triangle, set aside
- Using the large equilateral triangle and the 3 remaining yellow obtuse angles isosceles triangles, form a hexagon by placing the 3 triangles around the large triangle’s sides, ensuring the black lines match
- Ask the child “what shape have I made?” (child should answer hexagon)
- Fold the 3 yellow obtuse angled isosceles triangles into the equilateral triangle, so that the child can see the hexagon is made up of 2 equilateral triangles
- Slide the top 3 triangles off so the child can see the 2 equilateral triangles side by side (child can also see 3 obtuse angled isosceles triangles makes an equilateral triangle)
- Fold the 3 obtuse angled isosceles triangles back out so there is now a space in the middle (space forms an equilateral triangle)
- Ask the child “do you think we have any shapes that will fit in this space?”
- Place the large equilateral triangle on top to show it is the same size as the 3 obtuse angled isosceles triangles which make up an equilateral triangle
- Ask the child “do you think the rhombus will fit on top of the hexagon?”
- Pick up the rhombus and place it on top of the hexagon
- Separate out the shapes so the child can see that a hexagon is made up of 3 rhombi
- Take the rhombus off and set aside, reassemble the hexagon
- Ask the child “do you think we can fit the parallelogram on top of the hexagon?”
- Put the parallelogram on the hexagon demonstrating to the child that it does not fit
- Take the parallelogram off and reshape into a different parallelogram saying to the child “I wonder if we can change this into something else so it can fit?”
- Slide one of the triangles turning the parallelogram into a rhombus
- Place the rhombus onto the hexagon
- Separate out the shapes so that the child can see that a hexagon is made up of 3 rhombi
- Mix up all the shapes
- Invite the child to do the exercise
Variations
- The child may now work with this set with the previous 3 sets shown
