Abstract: An instructive clock with removable numerating strips mainly includes a clock having time scales provided on a face thereof to show a time point indicated by hour, minute, and second hands of the clock; and at least one numerating strip in the form of an elongated strip for annularly fitting on the clock. The at least one numerating strip is provided on a front side with time marks corresponding to the time scales provided on the clock, and at two ends with corresponding female and male connectors that could be fitly engaged with each other.

Abstract: A building block includes a cube, five of six sides of which is respectively provided with four through holes while the sixth side is diagonally symmetrically provided with two projections and two through holes. The building blocks may be connected to one another in many different manners to create various shapes, and could be conveniently stored in a closed container and produced at reduced cost.

Abstract: The present invention discloses an improvement structure of a game circle. The game circle mainly includes four same arcs, and axis set on the game circle, the axis is formed by a fixing element fixed into a through hole, and the fixing element is formed as one at one end of the arc, and the through hole is at another end of the arc; a recess set at the center of the fixed element, and the fixing element with flexibility when fixing something fixes arc together. By the way, the benefits of replacing rapidly and reducing cost can be reached.

Abstract: An improvement structure of a ruler, comprising: two rulers; an axis, composed of a hollow axis and a fixed axis, said hollow axis and said fixed axis being formed as one respectively to the ends of said rulers, said hollow axis being composed of an upper ring and an lower ring to combine said two rulers as one. Therefore, an improvement structure of the ruler of fewer elements, low cost and replacing rapidly can be obtained.

Abstract: A teach-aiding weight set includes a white, a red, a light green, a purple, a yellow, a green, a black, a brown, a blue, and an orange weight. Each of the weights is provided with spaced shallow grooves to show a plurality of equal sections corresponding to a specific weight thereof. The specific color, weight, and shallow-groove-divided sections of each of the weights help small children to learn primary mathematical concepts, particularly the concept of weight.

Abstract: A carton serving as a package for a Transformable Pyramid, which is a built-up type intellectual teaching aid, is produced from a cardboard divided into two groups of four right triangular faces for folding into first and second pyramidal parts, respectively. The first and the second pyramidal parts in the folded state provide two open-bottomed four-face pyramidal bodies connected and closable to each other to fitly enclose the Transformable Pyramid therein. Instructions of use and color strips showing outer appearance of the Transformable Pyramid may be printed on front and reverse surfaces of the eight faces of the carton. The carton therefore has the advantages of occupying a reduced space, and providing a fit package with instructions to facilitate display and promotion of the packaged goods.

Abstract: A sectional cubic block includes a plurality of layers of structural elements, a smallest one of which is an elementary cube and the other ones are proportionally increased in dimensions based on the elementary cube and all include three plane walls that separately extend in directions of x, y and z axes and therefore define an inner space adapted to receive a next smaller structural elements therein. Each of the structural elements, except the smallest one, is formed from a plurality of elementary frames sequentially proportionally increased in dimensions based on the elementary cube. Each of the elementary frames includes three continued right-angled parts that are respectively included in three planes extended in the directions of x, y and z axes. This particular configuration of the elementary frames enables children to freely stack the elementary frames to create many changeful shapes.

Abstract: A union is adapted to butt two reused plastic bottles at their mouths to provide a teaching aid for simulating the forming of spring and convection due to a pressure difference between two spaces. The union includes a hollow tubular body having a radially extended middle partition. An internal screw thread is provided on an inner wall surface of the union at each side of the middle partition to engage with an external screw thread on the mouth of the plastic bottle. The middle partition is provided with two symmetrical through holes, each of which is axially divided into two parts by a radially inward projected annular rib. Each part of the through holes is sized for a suction tube of predetermined dimensions to insert thereinto.

Abstract: A semi-circular protractor is provided at a center of circle with a through hole to which an auxiliary ruler having a length close to a diameter of the protractor is detachably and rotatably attached. With the auxiliary ruler, the protractor may be used to measure angles on a plane and on a three-dimensional body and to draw different angles. The protractor with the auxiliary ruler is designed for children to more easily understand the meaning of “angle” and to learn to use angles.

Abstract: A set of universal blocks includes a plurality of uniform-sized cubic elements, a plurality of uniform-sized connecting elements, and at least one disassemble aid. The cubic element each is provided at all six sides with an insertion hole each. The connecting element each is adapted to insert into the insertion holes on the cubic elements and has a length twice or almost twice as long as that of the insertion holes. The disassemble aid is a long flat element provided with a plurality of through holes adapted to easily disassemble the connecting elements from the cubic elements. The cubic elements may be freely connected to one another via the connecting elements to create a variety of two-dimensional and three-dimensional geometric shapes, and be conveniently used to play various kinds of games, including puzzles.