Old Stone AgeScience & Math Ishango bone c. 20,000 BCENotable A notched bone from Congo may record counting or a lunar calendar, an early hint of mathematics. ▲ MattersSaveShareTrace roots Longest chain: The Big Bang → First stars ignite → Supernovae seed heavy elements → The Sun forms → Earth forms → First oceans → First life → Photosynthesis evolves → Great Oxidation Event → Complex cells (eukaryotes) → Multicellular life → First animals → Cambrian Explosion → First vertebrates → Jawed fish → Fish walk onto land → The amniotic egg → The Great Dying → Dinosaurs appear → Asteroid ends the dinosaurs → Early primates → Apes split from monkeys → Human line splits from chimpanzees → Walking upright → First stone tools → Genus Homo appears → Homo erectus → Control of fire → Habitual fire and cooking → Homo sapiens appears → Complex language → Ishango bone Community notesLoading notes… Learn more ranked by votesBookClaudia ZaslavskyAfrica Counts ↗Editor's pickBookGeorges IfrahThe Universal History of Numbers ↗Editor's pickVideoSearch on YouTubeIshango bone mathematics ↗Editor's pick