- A box containing one Black and White Short Bead Stair.
- A box containing 2 Colored short Bead Stairs.
- A box containing a minimum of 9 Ten Bead Bars.
- A small felt mat to work on the table.
- Directress shows the child how to make a triangle with the Black and White Bead stair, saying "This is how we make the triangle".
- Directress invites the child to build the 2 sets of Colored Beads into triangles.
- Then directress says, "Now we are going to make a snake with the colored beads" and she takes any of the colored beads at random and starts to lay out a snake..
- Then the Directress explain to the child that "we are going to change the Colored Snake to a Golden Snake, using the Golden Ten Bead Bars"
- The Directress begins to count to 10. If the colored Bead bars are 4,2,8,...beads. The tenth Bead will be reached on the fourth bead of the Eight Bead Bar, leaving 4 over. The Directress puts a marker in place at the end o the tenth bead, removes the 4,2 and 8 bead bars and places them on the lids. She then replaces them with one golden Ten bead Bar and a 4 from the Black and White Bead Bars.
- Directress then proceeds to count the next 10, starting from the Black and White Beads. The whole idea is to replace every ten bead with a Golden Ten Bead Bar and the remainder units with the Black and White Bead Bars.
- At the final stage, the exercise would have been carried out correctly if the whole snake has turned golden. If not, that means there was an error that had occurred in the process of the exercise.
- When the above exercise has completed, the Directress then proceeds to this exercise, saying "Now we check to make sure all the numbers add up to 10".
- She lay out all the Golden Bead Bars.
- The Directress takes a Nine Bead Bar, says "This is nine, we need one more to make ten" and she takes a One Bead Bar, place them together next to the first Golden Ten Bead Bar. She then takes a One Bead Bar and says, "This is one, we need nine more to make ten" and she takes a Nine Ten Bead Bar, place them together beside the next Golden Ten bead Bar.
- She continues to do the same for 8 and 2, 2 and 8, 7 and 3, 3 and 7, ....etc.
Control Of Error
The Black and White Bead Stair provides a control of error when the child changes Colored Beads for Golden Beads. (One of the lids is used to hold, and later check, the Beads removed from the snake).
Points Of Interest
- Prepare the child for addition.
- Indirect preparation to Number Bonds and commutative law.
<a href="http://www.montessorimaterials.org/Math/PSG1stream.wmv" target="_blank">Snake Game Video</a>