ASU 085 All Soviet Union MO 1967 rearranging digits of a natural
Source:
June 20, 2019
number theoryDigits
Problem Statement
a) The digits of a natural number were rearranged. Prove that the sum of given and obtained numbers can't equal ( of nines). b) The digits of a natural number were rearranged. Prove that if the sum of the given and obtained numbers equals , than the given number was divisible by .