MathDB

8.2

Part of 2021 Kyiv City MO Round 1

Problems(1)

Erased digit

Source: Kyiv City MO 2021 Round 1, Problem 8.2

12/21/2023
Oleksiy writes all the digits from 00 to 99 on the board, after which Vlada erases one of them. Then he writes 1010 nine-digit numbers on the board, each consisting of all the nine digits written on the board (they don't have to be distinct). It turned out that the sum of these 1010 numbers is a ten-digit number, all of whose digits are distinct. Which digit could have been erased by Vlada?
Proposed by Oleksii Masalitin
number theoryDigits