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

The video tutorial explains autobiographical numbers, where each digit describes the frequency of digits in the number. It guides viewers through solving for a ten-digit autobiographical number by analyzing patterns and applying logical deductions. The solution involves understanding constraints, such as the sum of digits equaling ten and limiting large digits. The tutorial concludes with the correct sequence of digits, revealing the ten-digit number.

What is an autobiographical number?

• A number that describes its own digits

• A number that is a palindrome

• A number that is prime

• A number that is divisible by its sum of digits

Why can't a ten-digit autobiographical number have multiple large digits?

• Because it would exceed the total number of digits

• Because large digits are not allowed

• Because it would make the number a palindrome

• Because it would make the number prime

What is the sum of the digits in a ten-digit autobiographical number?

• 10

• 9

• 11

• 12

How many non-zero digits can appear after the first digit in a ten-digit autobiographical number?

• Four

• Five

• Two

• Three

What is the unique ten-digit autobiographical number?

• 4210100000

• 1210000000

• 3211000000

• 6210001000