Interesting things that you did not know about Africa..... - Africans pioneered basic arithmetic 25,000 years ago. The Ishango bone is a tool handle with notches carved into it found in the Ishango region of Zaïre (now called Congo) near Lake Edward. The bone tool was originally thought to have been over 8,000 years old, but a more sensitive recent dating has given dates of 25,000 years old. On the tool are 3 rows of notches. Row 1 shows three notches carved next to six, four carved next to eight, ten carved next to two fives and finally a seven. The 3 and 6, 4 and 8, and 10 and 5, represent the process of doubling. Row 2 shows eleven notches carved next to twenty-one notches, and nineteen notches carved next to nine notches. This represents 10 + 1, 20 + 1, 20 - 1 and 10 - 1. Finally, Row 3 shows eleven notches, thirteen notches, seventeen notches and nineteen notches. 11, 13, 17 and 19 are the prime numbers between 10 and 20.
Posted on: Mon, 10 Jun 2013 11:33:20 +0000
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