Calculators - Xnumber World of Calculators - James Redin
This is a gateway to the magical world of calculators. Explore the history of these wonders of technology, and find information about current products and trends including a patent for an improved numerical keyboard.
X-Number, Xnumber patent, verbal numerals, extended numerical keyboards, vintage calculators, early calculators, old calculators, mechanical calculators, electronic calculators, troncets, calculator collectors, collecting calculators, calculator collectio
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