In 1025, two learned monks, Radolph of Liége and Ragimbold of Cologne, exchanged several letters on mathematical topics they had encountered while reading a manuscript of the sixth-century Roman philosopher, Boethius, whose writings supplied one of the few mathematics sources in the Middle Ages. These monks were not mathematicians, but they were inquisitive and keen to further their learning. They pondered Boethius’ words. They struggled. In particular, they puzzled over the theorem that the interior angles of a triangle were equal to two right angles. “Interior angles” of a triangle? What could that possibly mean? Neither had a clue. Even the mathematically averse among us today recognize the basic geometry that Radolph and Ragimbold failed to grasp, for we live in a numerate society, surrounded by countless manifestations of mathematics. Broadly defined as the ability to reason with numbers and other mathematical concepts, numeracy underlies our current information explosion. Its clichés dot popular speech: “do the math,” “crunch the numbers,” … Continue reading When Numeracy Superseded Literacy—and Created the Modern World