Teaching aid for mathematics
CA 1114602 A · Owner: Ropchan, George · Inventors: Ropchan, George
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An arithmetic teaching aid For demonstrating the spatial relationship between positive and negative numbers to enable the teaching of operations in the set of integers and includes a, mirror surface with an arm projecting at an angle of ninety (90°) degrees therefrom and having integers representing positive numbers spacedly and vertically arranged thereon so that the images of integers reflected by the mirror surface will indicate to students viewing from, the front, negative integers and their relationship to the positive integers.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted December 22, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended December 22, 1998.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.