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Keywords from Image Description:
Fotothek df tg Geometrie Mathematik Arithmetik Proportion Rechenscheibe. Scan Deutsche Fotothek dftg color MIKCenter Berlin GmbH Frankfurt Main Proportionsspiegel Papier Kupferstich cm Geometrie Mathematik Arithmetik Proportion Rechenscheibe ppn Druck Deutsche Fotothek gefrdert von der Deutschen Forschungsgemeinschaft