发明名称 Metric unit conversion aid
摘要 A template incorporating a plurality of openings forming columns and rows having a predetermined alignment and identified by annotations representing metric system units to facilitate use of the device for automatic unit conversion during the performance of mathematical calculations involving dissimilar metric unit quantities.
申请公布号 US4021923(A) 申请公布日期 1977.05.10
申请号 US19760648956 申请日期 1976.01.14
申请人 FELDMAN, DEVORA 发明人 FELDMAN, DEVORA
分类号 G06G1/00;(IPC1-7):G09B19/02 主分类号 G06G1/00
代理机构 代理人
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