STEM
Ancient African mathematics you can teach today
From the Ishango bone to Yoruba base-20 arithmetic, three ready-to-teach lessons that show math as a global inheritance.
The Ishango bone, unearthed near Lake Edward on the Democratic Republic of Congo–Uganda border, is roughly 20,000 years old. Carved into it are three columns of tally marks that group into prime numbers and doubling sequences. Whatever its exact purpose, it is one of the oldest known mathematical artifacts on Earth. Lesson: give students a blank "bone" strip and ask them to invent a notation for the count of something they care about.
The Yoruba of Nigeria count in base 20 with subtractive shortcuts: 45 is expressed as "five from three twenties." Students who struggle with place value in base 10 often light up when they see that number systems are choices, not laws. Try a short unit converting between base 10 and base 20.
The Lusona sand drawings of the Chokwe people of Angola are traced in a single unbroken line around a grid of dots — an early form of graph theory and Eulerian path analysis. Print a grid, tell the story, and let students discover which patterns can be drawn without lifting the pencil.
Math history taught this way stops being a European relay race and becomes what it always was: a human one.