Across
- 6. Italian mathematician who introduced Indian numerals to medieval Europe in his 1202 Book of Calculation
- 8. Rotates: what the Earth does on its axis — a fact Indian scientists established long before Europeans accepted it
- 9. Greek philosopher and mathematician who believed the entire universe was made of numbers
- 10. The caliph who ruled Baghdad and received the gift of Indian numerals from an ambassador — transforming Islamic mathematics
- 11. Ancient Mesopotamian civilisation that first used clay tokens to represent numbers and invented arithmetic
- 14. An Indian cosmic unit of distance: the path covered by a deity travelling a million kilometres per blink of an eye for six months
- 16. British location where the world's first working binary computer was installed to crack German codes in World War II
- 18. The mathematical operation first made possible by Sumerian clay tokens — adding and taking away
- 21. Ancient country whose philosophers asked what everything is made of — and whose thinkers pioneered theoretical mathematics
- 23. The country in which zero was invented, and whose scientists proved the Earth orbits the Sun — a thousand years before Copernicus
- 25. The Ishango ___: a 20,000-year-old counting object found in what is now the Democratic Republic of Congo
- 26. Small clay object used by the Sumerians to represent a quantity; the world's first physical symbol for the number one
- 28. 17th-century mathematician who invented the binary system, convinced that one and zero were the only numbers the universe truly needed
Down
- 1. African country where the Ishango bone — evidence of counting some 20,000 years ago — was unearthed
- 2. A frame with beads or counters used for calculating in medieval Europe; eventually defeated by Indian numerals
- 3. Symmetrical about its centre — like a well-balanced number system where position determines value equally on both sides
- 4. City in northern India where the oldest known written zero is carved inside a small temple
- 5. Ancient Greek city-state where Archimedes was born, lived and killed — cradle of theoretical mathematics
- 7. Religious community members; in medieval Europe, they were among the guardians of mathematical and scholarly knowledge
- 8. The Arabic word for zero, which also gave us our English word for a secret code
- 12. Ancient civilisation that defined the cubit as a standard unit of measurement for its monumental building projects
- 13. Greatest mathematician of ancient times, killed by a Roman soldier in Syracuse in 212 BC whilst deep in calculation
- 15. Describes a city-dweller; the Sumerians needed arithmetic partly because so many people lived together and had to share grain
- 16. Capital of the Islamic caliphate in the 8th century, where an Indian ambassador presented the gift of Indian numerals
- 17. An almost unimaginable unit of time in Indian philosophy: it would take one to build a 10km cube of wool, one strand per century
- 19. Name of the 20,000-year-old animal bone found in the Congo, one of the earliest pieces of evidence for counting
- 20. The number whose first undisputed written example was found in Gwalior — and which later teamed up with one to rule the digital world
- 22. The number system invented by Leibniz, made of only ones and zeros, and used by all modern computers
- 24. To work out or deduce — what a mathematician does when reasoning from numbers to conclusions
- 27. Egyptian unit of length: the distance from the elbow to the tip of the middle finger