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Summary

DescriptionAbacusBeansFiveTen.PNG	This is the small abacus of Al-Khwārizmī abacus with base-five/ten. All upper beans have the five values, and all down beans has the ten values. Hypothetically, this kind of abacus was used on the paleography of modern numerals: five, six, seven (down beans) and eight, nine, ten (upper beans). It is assumed to have originated because humans have ten fingers.
Date	born around 780 and died around 850
Source	http://en.wikipedia.org/wiki/Muhammad_ibn_Musa_al-Khwarizmi
Author	Al-Khwārizmī

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