Ten brown-stained (or painted) wooden prisms that range progressively from 1x1x20 cm, 2x2x20 cm, 3x3x20 cm, up to 10x10x20 cm. Viewed from the side, one can see how they increase in size by the 2nd power, varying from the next in two dimensions; they represent the squares of 1 through 10.
- Invite the child to the lesson. Ask the child to watch.
- Starting with the largest rectangle on the left, carefully carry the rectangle with both hands.
- Place the rectangle in a random spot on the rug.
- Continue this process one rectangle at a time while inviting the child to help by doing the same.
- Once all the rectangles are placed randomly on the rug, look for the largest rectangle and pick it up with both hands, place it in the middle back of the rug so that it touches the edge of the rug.
- Continue this process by progressively picking up the next largest rectangle and placing it directly in front of and touching the previous rectangle, aligning the sides.
- Once the stair is complete, invite the child to walk around the stair with you and to look at the stair from different angles.
- Piece by piece, carefully take the brown stair apart and randomize it.
- Invite the child to now build the brown stair.
Exercise 1, the child performs as presented.
Exercise 2, do the same thing as exercise 1 except take the smallest rectangle and “walk up and down the stairs” by carefully picking up the rectangle and placing it on the next stair, and aligned with the edge of the stair. After placing it on each stair, disassemble, and let the child perform the exercise.
Thin, thick, thinner, thicker, thinnest, thickest.
Grading at a Distance: Place two rugs on the floor far apart from one another. Place all the rectangles on one rug, and request the child to build the stair on the other distant rug by asking him to bring the thickest rectangle, and then the next thickest rectangle, and so on.
Thicker or Thinner: Sit away from the rug and hold a random prism, request the child to bring a thicker or thinner prism from the rug.
Control of Error
Lies within child, visual as rectangle won’t make a progressive stair if they are out of order.
Visual discrimination of dimension.
Refinement of voluntary movement, preparation for the mathematical mind, muscular education of the grip.
3 – 3 ½
The prisms vary in two dimensions instead of three.
The goal is build the intellect.