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Two Chinese men use the abacus to calculate for their business. "The abacus was one of the earliest aids to calculation." -Hill, 1921

Chinese Abacus

Two Chinese men use the abacus to calculate for their business. "The abacus was one of the earliest…

Used in businesses and bookkeeping, the adding machine was a device used for calculations. "One of the first successful adding and listing machines (courtesy of the Burroughs Adding Machine Company)." -Hill, 1921

Adding Machine

Used in businesses and bookkeeping, the adding machine was a device used for calculations. "One of the…