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Mind-Bending Math & GamesRecreational Mathematics

The Mysterious 6174

Any four-digit number falls into the same number

Any four digits, one simple subtraction done over and over, and everyone lands on the same number. Why does every road lead there?

You'll find out

  • A subtraction that pulls numbers in
  • How many steps the slowest start needs
  • The digits that refuse to play

Why it matters

It is a magic trick for any calculator, and a first taste of how simple rules can hide surprising patterns.

About 3 min6 interactive slides · 5 questionsLesson 99 · Zone 11

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