Blocks with mating bosses and recesses which bulge for interfere

Details Blocks with mating bosses and recesses which bulge for interfere Blocks with mating bosses and recesses which bulge for interfere

1990-10-29

1993-08-24

Wilson, John J.

Education and demonstration

Mathematics

Arithmetic

434208, 434403, 446117, 446121, 446 87, G09B 1902, G09B 100

Patent

active

052384071

ABSTRACT:
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.

REFERENCES:
patent: 349646 (1886-09-01), Grigg
patent: 1305724 (1919-06-01), Kennedy
patent: 2278894 (1942-04-01), Paulson
patent: 2440205 (1948-04-01), McLain
patent: 3577671 (1971-05-01), Woollett

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