I don't know if this has been posted already, but anwho...(adsbygoogle = window.adsbygoogle || []).push({});

If you pick any positive integer greater than 9 and subtract the sum of its digits from that number, you'll end up with a multiple of 9. How do I know it's a multiple of 9? Curiously enough, the sum of the digits of a positive integer that is a multiple of 9 is a multiple of 9. Do this enough times and you'll end up with 9.

I tried this with other number systems and it seems to hold. This is the most interesting play of numbers if found to date.

**Physics Forums - The Fusion of Science and Community**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Sum of Digits Always Nine

Loading...

Similar Threads - Digits Always Nine | Date |
---|---|

I Is a symmetric matrix with positive eigenvalues always real? | Jan 26, 2017 |

Any number operated by modulus operator gives remainder as the last digit of the number? | Oct 21, 2014 |

Discovering formula for a sequence with recurring digits | Aug 31, 2012 |

How to find 'self locating digits' in irrational numbers | Aug 3, 2012 |

Finding a formula for a sequence with recurring digits | Jul 26, 2012 |

**Physics Forums - The Fusion of Science and Community**