Arithmetic instructional apparatus

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Description

FIG. 1 is a plan view of a arithmetic instructional device showing my new design;

FIG. 2 is a side view of the arithmetic instructional device of FIG. 1; and,

FIG. 3 is a bottom view of the arithmetic instructional device of FIG. 1.

The FIG. 1 view has been shaded to indicate color.

Referenced Cited
U.S. Patent Documents
199721 January 1878 Knight
284576 September 1883 Rowland
D354314 January 10, 1995 Steininger
666070 January 1901 Schleicher
962441 June 1910 Lerner
1662503 March 1928 Krieger
2567497 September 1951 Sorensen
2908439 October 1959 Evans
3419973 January 1969 Manotas et al.
3624928 December 1971 Felton
4372742 February 8, 1983 Wentworth
4399353 August 16, 1983 Adkins et al.
4424039 January 3, 1984 Washburn
4445865 May 1, 1984 Sellon
4790757 December 13, 1988 Takahashi
5018976 May 28, 1991 Kuyath
Patent History
Patent number: D392674
Type: Grant
Filed: Apr 21, 1997
Date of Patent: Mar 24, 1998
Inventor: Irma Maritza Perez (Bloomfield, NJ)
Primary Examiner: Martie Thompson
Application Number: 0/69,494
Classifications
Current U.S. Class: Teaching Material (D19/59); Movable Indicator Or Changeable Exhibitor (D19/64)
International Classification: 1907;