In 1931, a group of archaeologists found a 4.000-year-old Sumerian clay tablet in Kish, present-day Iraq. It was a small tablet depicting a Babylonian mathematical task.
Kish, along with Babylon, was a center of mathematical learning in ancient times, where numerous schoolwork tablets have been found, some with the teacher's calculations on one side and the student's on the other.
What was not known at the time is that the tablet had left behind a calculation error for posterity: a student made a mistake when calculating the area of a triangle.
The tablet is now part of the digitised collection of the Ashmolean Museum at the University of Oxford and is a unique window into the methods of learning and knowledge transmission in ancient Sumeria.
On the cuneiform engraving, the student inscribed the values of 3.75 for the height and 1.875 for the base of the triangle. However, when calculating the area, he made a mistake, recording 3.1468 instead of the correct value, 3.5156.
The error highlights a crucial shift in the culture of the time: the shift from oral memorization to the written record of knowledge.