BROUKOID: aha, no já jsem na historii nikdy moc nebyl a to ani na historii matematiky. Tak jsem si to nechal zkontrolovat uměláka. A dle jeho tvrzení fakticky žádná z metod nesouvisí s uvedeným autorem. Což je vtipné. Ověřovat více to po něm nebudu.
Each panel is a real, valid way to compute 55×55 = 3025, but the attributions are mostly mythology — internet folklore that pins ancient or anonymous techniques onto famous names.
1. "Galileo" — Area / binomial expansion
Splits 55 = 50+5, then (50+5)² = 2500 + 2(250) + 25 = 3025.
Real origin: Euclid, Elements Book II, Prop. 4 (~300 BCE). The Babylonians used it even earlier. Galileo (1564–1642) was a physicist/astronomer, not the source.
2. "Newton" — Difference of squares
Uses a² = (a−b)(a+b) + b², so 55² = 50·60 + 25 = 3025.
Real origin: Also Euclid, Elements II.5. A standard ancient identity, not Newton's.
3. "Zu Chongzhi" — Long multiplication in columns
The familiar schoolbook algorithm.
Real origin: Developed in India, transmitted via al-Khwarizmi (9th c.) and Fibonacci's Liber Abaci (1202). Zu Chongzhi (5th c.) is famous for computing π to seven digits using counting rods — a different system entirely.
4. "Ramanujan" — Stick/line multiplication
Draw 5 lines for each digit, count intersections in groups: 25 / 25+25 / 25 → 3025.
Real origin: Anonymous viral method, often mislabeled "Japanese," "Vedic," or "Chinese." No documented historical author. Ramanujan worked on infinite series and number theory, not visual arithmetic tricks.
5. "Leibniz" — Lattice (gelosia) multiplication
Grid with diagonals; sum along the diagonals.
Real origin: Indian mathematics ~10th century, brought to Europe by Fibonacci in 1202 — over 400 years before Leibniz (1646–1716).
6. "Gauss" — The "ends-in-5" shortcut
For n5 × n5: compute n(n+1), append 25. So 5·6 = 30 → 3025.
Real origin: A consequence of (10n+5)² = 100n(n+1) + 25. Known to medieval Arab mathematicians and appears in Trachtenberg-style mental math. Gauss never claimed it.