Arithmetic Bead String
red/blue with 100 balls
Arithmetic String (approx. 150 cm) with 100 balls in a step of 10 on a tearproof, stretchable string. The balls are made of RE-Plastic® (Ø 1cm). When pulling the string, the slight ball lock lifted and all beads slide back together again.
Packed in polybag.
This could also be interesting:
count forwards and backwards from 1 to 20 grasp quantities at a glance decompose quantities (7 decomposed into e.g. 5 and 2) count in steps...