Abstract: The apparatus is used as a teaching aid for arithmetic, metric and analytical geometry and elementary algebra, and is formed by a cubic block array comprising a plurality of different size blocks arranged in rows and columns. The cubic block array has a base array of ten-by-ten blocks commencing with a one centimeter block and progressing in x and y rows with increasing length blocks (1 cm., 2 cm., 3 cm., etc.), and overlying arrays of the same pattern but progressively increasing in height (1 cm., 2 cm., 3 cm., 4 cm., etc.).