MathDB
Problems
Contests
National and Regional Contests
Russia Contests
All-Russian Olympiad
1999 All-Russian Olympiad
1
Sum of digits of 9A
Sum of digits of 9A
Source: All-Russian MO 1999
December 31, 2012
number theory
Problem Statement
The decimal digits of a natural number
A
A
A
form an increasing sequence (from left to right). Find the sum of the digits of
9
A
9A
9
A
.
Back to Problems
View on AoPS