The educational math toy includes various embodiments, each having a triangular configuration. The toy is based upon the concept that two numerical factors will always provide a solution when manipulated by a mathematical operation, with the two factors being shown at two corners and the solution being shown at the third corner of the triangle. One series of embodiments includes variations on a mechanical device containing a central idler gear and a series of three outer gears arranged in a triangular array in a housing. The gears, or interchangeable display discs used therewith, rotate in registry, with each displaying one of a series of numbers through corresponding windows in one or both faces of the housing. The monolithic tiles are arranged in the same manner, but display only one fixed set of factors and one solution on each face. Braille may be used in lieu of numbers, if so desired.