Abstract: An arithmetical manipulative device comprises a plurality of tiles, each tile having an upper surface, a lower surface, a first end and a second end, and a connector member for connecting the first end of one tile to the second end of a neighboring tile. The connector member is configured such that the one tile and the neighboring tile are pivotable relative to each other between a position wherein the upper surface of the one tile lies substantially adjacent the upper surface of the neighboring tile and the lower surface of the one tile lies substantially adjacent the lower surface of the neighboring tile. Further, the connector member is releasably connected to at least the one tile or the neighboring tile to permit a selected number of tiles to be serially assembled with respect to each other. The invention is also for a method for making arithmetical calculations.