Jumbo Arithmetic Bead String
red/white with 20 balls
20 red / white balls (Ø 2.5cm) from RE-Wood®, in a step of 5 on a 100cm long string.
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...
Counting forward and backward from 1 to 100 Addition - adding with and without passing tens multiplication - multiply division - dividing -...