The peoples of Africa employ a wide variety of systems for counting objects or representing numbers. Many of these are verbal systems, others involve gestures, and some use pictures or other counting devices.
Verbal number systems use words to express quantities. Most are founded on the numerical bases of 5, 10, and 20. For example, the Makhwa of MOZAMBIQUE use five (thanu) and ten (nloko) as bases. Their expression for six is “thanu na moza,” or “five plus one.” To describe 20, they say “miloko mili,” or “ten times two.” Some verbal number systems also use subtraction to form number expressions.
Many African groups traditionally use gestures to count and describe numbers. The Yao of MALAWI and Mozambique represent the numbers one through four by pointing with the thumb of the right hand at extended fingers on the left hand. Making a fist with the left hand indicates the number five. Raising the fingers of both hands and joining the hands together is the signal for ten.
Visual number systems employ devices such as knotted strings or sticks. For example, Makonde women of TANZANIA and Mozambique tie a knot in a string at each full moon to keep track of how many months it will be until they give birth. The FULANI herders of Nigeria place sticks in front of their houses to indicate how many cattle they own. A “V” indicates 100 animals, an “X” symbolizes 50, and an “I” indicates single animals. In front of one particularly wealthy household the following arrangement of sticks was found—VVVVVVXII, indicating that the owner of the house had 652 cows.