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For each positive integer n, let S(n) denote the sum of the digits of n. How many three-digit n's are there such that  

\(n+S(n)+S(S(n))\equiv 0 \pmod{9}?\)

 

Thanks for helping! Also- please explain your answer so I can better understand it!

 Sep 17, 2020
edited by PocketThePenguin  Sep 17, 2020
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There are 24 positive integers n that work.

 Sep 17, 2020

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