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Can you solve the Leonardo da Vinci riddle? - Tanya Khovanova

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TEDEd Animation

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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.

WatchThink 5 Multiple Choice &
3 Open Answer Questions Dig Deeper Learn More Discuss 1 Guided Discussion &
1 Open Discussion
The first digit of an autobiographical number counts the number of its zeros. There are 2 autobiographical numbers with 4 digits. But there are many more 4-digit numbers in which the first digit equals the number of zeros. How many 4-digit numbers have their first digit count the number of zeros?

About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

Meet The Creators

  • Educator Tanya Khovanova
  • Director Outis
  • Narrator Addison Anderson
  • Script Editor Alex Gendler
  • Animator Nemanja Petrovic
  • Content Producer Gerta Xhelo
  • Editorial Producer Alex Rosenthal
  • Associate Producer Bethany Cutmore-Scott, Elizabeth Cox
  • Fact-Checker Brian Gutierrez

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