发明名称 Blocks with mating bosses and recesses which bulge for interference fit
摘要 Base-ten blocks for teaching arithmetic to children, in which each block (19) has a projecting boss (27) with curved (bowed-out) sides (29) and an aperture (33) with straight sides (35), so that blocks (19) can be securely joined together to form multiples of units. Integrally made rows (37) of ten blocks each have two end bosses (41) for joining to other rows (37) to make flats (47) of one hundred units. Each flat has four bosses (51) for joining to other flats (47) to make a cube of one thousand units. The blocks have one color for units, a different color for rows of tens, a different color for flats of one hundred, and a still different color for cubes of one thousand. The blocks can be used to teach addition, multiplication, subtraction, division, etc., to children.
申请公布号 US5238407(A) 申请公布日期 1993.08.24
申请号 US19900604930 申请日期 1990.10.29
申请人 POLLOCK, CLYDE 发明人 POLLOCK, CLYDE
分类号 G09B1/36;G09B19/02 主分类号 G09B1/36
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