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Die große Enzyklopädie des mechanischen Rechnens

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Patent:GB191317890


Brevet:GB 191317890
Titre:Abacuses
Date:05.08.1913
Lieu:
Pays:Royaume-Uni
Personne:Montessori, Maria (P)
Entreprise:
Liens internes:Abakus Lehrmittel
Mots-Clefs:
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 GB191317890


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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.