Abstract: An instructional toy device for multiplication computation formed by a string of cuboid blocks having an interconnecting elastic string permitting equal segments of multiple blocks to be folded in a back and forth arrangement of aligned rows, the blocks each being individually marked with a number progressing in an ordinary arithmetic series of increasing units from an end block marked 1 to an end block marked with the number of the total blocks in the string, a multiplication computation being represented by a selected number equalling the number of blocks in a segment and a multiple equalling the number of rows, the product of which is the numerical marking of the last block in the segment of the last row.