The devices for teaching elementary fractional concepts each include a board having a raised periphery and central depression representing unity. Each embodiment includes a series of fractional pieces of different sizes for removable installation therein, with the number of pieces of each size having a total span equal to the span of the central depression. Thus, each piece represents the denominator of a fractional portion of the central recess. The pieces may be stacked in several layers, thus demonstrating the equivalency of different sizes of fractional pieces subtending the same area of the recess. The devices may be formed in rectangular or circular configurations, and may represent the basic abstract concept of fractions, monetary values in different systems, time and divisions thereof, etc. Separate boards may be provided for each embodiment, or inserts may be provided for placement within recesses of correspondingly configured boards.