Addition strip board

The material, completely made of birch wood and with non-toxic varnishes, consists of:
- a square board engraved with the numbers 1 to 18 at the top. The maximum number is 18 because it is the maximum number that can be assembled with the largest rods: 9+9. The number of vertical squares is 10 because, in the base 10 system, this is the maximum number of possible combinations. The vertical red line at the 10 visually and clearly signals to the child the passage of numbers through the 10.
- a box without a lid, which contains two sets of rods: nine blue and nine red, both of the same height as the squares and varying in length from 1 to 9 squares.

Handcrafted product made in Italy with certified raw materials.