Patent:GB191317890

Da Rechnerlexikon, l'enciclopedia ...


Brevetto:GB 191317890
Titolo:Abacuses
Data:05.08.1913
Luogo:
Nazione:Gran Bretagna
Persona:Montessori, Maria (P)
Ditta:
Link interni:Abakus Lehrmittel
Keywords:
Link al brevetto:
(without guarantee)
 GB191317890 (http://v3.espacenet.com/textdoc?DB=EPODOC&F=0&IDX=GB191317890)


Enlarge

Aus der Patentschrift GB191317890

A device for teaching the writing of numerals employs differently coloured rows of ten beads, the left hand standard of the frame being marked to indicate the unit, tens, &c. rows. The numbers represented are written upon cards ruled with lines corre- sponding in colour, number, and sequence with the rows of beads.

Ricavato da "http://www.rechnerlexikon.de/it/wiki.phtml?title=Patent:GB191317890"
Ultima modifica il 18:27, 29. Ott 2007.