A wooden tray contains : 1) ten bars of each coloured bead bars 1-9 in a wooden compartment box; 2) 5 bars of each of the grey bead bars 1-9 in a wooden box; 3) black and white bead stairs 1-9, plus 20 golden bead bards of 10 in a wooden compartment box. 1. Introduces the child to the unit combination of subtraction. 2. Teaches how to subtract concrete representation of negative functions. 3. Preparation for algebra (equal quantities of opposite sign eliminate each other).

Materials

Beech wooden box contains three boxes, three boxes each divided into a grid, two cells, 9 cell. A grid box is equipped with 1-9 gray beads rod 5, two boxes were equipped with 20 golden bead bars and 1-9 black and white phase beads stick, 9-cell box containing 1-9 beads of color 10 .
Color beads are handmade. Good surface treatment.
The white box

Purposes

1Corresponding to the relationship between the number and quantity
2 prepare for learning subtraction