The material consists in a set of wooden 15x15 cm green tablets with the numbers 1 to 9, plus a zero, engraved. The tablets are placed in a wooden open index box with two compartments. All wooden parts are UNI EN 71-3 finished.
From the age of 3 years the sandpaper numerals get the child acquainted with the grafical symbols corresponding to quantity through the presentation of linked units. It is used to prepare the hand for writing symbols so through touching, the form of the numeral is captured by the muscle memory. The sound is associated to the auditory memory, like when using sandpaper letters (LI03 and LI04). Sandpaper numerals can be used with other materials like the numeral rods (MA00).