TED-Ed

Can you solve the Leonardo da Vinci riddle? - Tanya Khovanova (2018x80)

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You’ve found Leonardo da Vinci’s secret vault, secured by a series of combination locks. Fortunately, your treasure map has three codes: 1210, 3211000, and… hmm. The last one appears to be missing. Can you figure out the last number and open the vault? Tanya Khovanova shows how. Lesson by Tanya Khovanova, directed by Artrake Studio