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

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TEDEd Animation

Let’s Begin…

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 Dig Deeper Discuss
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?

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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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