45 single white and black beads for Montessori Positive Serpent

45 beads for white and black for the Positive Snake, Montessori addition snake, mental calculation, addition memorization, not mounted in bars,
to design the Montessori positive snake black and white bead staircase by yourself

Introduction to memorizing addition, preparation for mental calculation.

Acrylic beads diameter 8mm drilling 1.4mm
Galvanized wire not supplied