abacus on a wooden stand

Description

An antique abacus on a wooden stand. Blue and red turned wooden balls that differ slightly in size. One ball is missing. Letters could be placed in the horizontal wooden slats on the other side of the abacus. A multifunctional teaching board, therefore, for both mathematics and language lessons. Probably early 20th century.
Height: 150 cm, width 83 cm, depth 35 cm.