Montessori Trinomial Cube Presentation
The trinomial cube is a wooden box with a cover and two adjacent hinged sides, containing 27 wooden blocks that fit together to form a cube with the same pattern on each side and in the middle. The cube has a visual representation of the algebraic formula (a+b+ c) (a+b+c) (a+b+c) or:
3 control charts
To help develop the child’s visual perception of three-dimensional patterns.
To prepare the child for later work in Maths, especially algebra.
To aid the child’s fine motor.
Eye- hand co-ordination.
To prepare the child for writing.
CONTROL OF ERROR:
The control charts
The child feels that all the blocks have the same dimension.
The colours of the cubes.
4 –5 years approx.
Individual exercise done at a table on a work mat.
Show the child how to carry the box and how to open and remove the box’s lid. Show the child how to lower the two adjacent hinged sides gently towards yourself. Show the child how to place the lid into the angle made by the opened sides, with the red square in the corner next to the box.
Place the control charts beside and slightly in front of the box.
Remove the top layer of cubes and place them on the furthest (a) control charts that you have placed in front of the cube. Place your flat hand on the cubes to ensure that they are all the same height.
Repeat this removal for the next layer placing them on the control chart closer to you (b) again feeling that they are all the same height.
Repeat this removal for the last layer, placing them on the control chart closest to you (c) again feeling that they are all the same height.
Beginning with the red cube, that is, the cubes on control chart (c) place the SHORTER dimension cubes back onto the lid of the box. Feel that they are all the same height.
Now place the TALLER cubes, on control chart (b) back onto the layer of cubes that are already on the lid of the box. Feel that they are all the same height with the flat of your hand.
Now place the TALLEST cubes, on control chart (c) back onto the layer of cubes that are already on the lid of the box. Feel that they are all the same height with the flat of your hand.
Beginning with the red cube from the top layer of cubes, replace them into the box wrapping the other cubes around the red cube. Place the blue cube in last. Feel with your flat hand that they are all the same height. Do the same for the second layer of cubes and for the third layer of cubes.
Once the cubes are all back, fold up the sides of the box and draw attention to the fact that the pattern of the cubes inside the box resembles the pattern on the lid.
Invite the child to have a turn.
The child can build the Trinomial cube in exactly the same way but outside the box without the control charts.
One day, after the cube is built outside the box, show the child that all the cube’s faces have the same pattern on them. Turn the cube around to show the child that the back faces are the same too. Place both hands around the cube and lift it, to show the child that the bottom also has the same pattern on it.
Show the child that the 12 inside faces have the same pattern. You will be able to do this by splitting the cube three ways, horizontally, vertically, and back to front. This will expose each face with each split.
Show the child how you can match all the faces of the cubes together. Build a horizontal line on the mat from left to right, matching all the same sized blue faces.
Do the same with the red, black and yellow faces
Invite the child to have a turn.
The child can independently build the three separate layers of the Trinomial Cube and put them together to make the complete cube, although the child should put them together piece by piece, rather than trying to lift each layer in its entirety.