There is evidence to suggest that African Mathematics
    began more than 8000 years ago. A carved bone dating from between 9000 BC
    and 6500 BC was found at Ishango in Zaire. The markings indicate that these
    prehistoric people used a base-10 number system (just like we do) and were
    familiar with prime numbers and the operation of multiplying by 2. A series
    of notches on the Ishango bone appear to approximate a lunar calendar,
    suggesting a fairly sophisticated knowledge of astronomy.