MathDB
Sum of digits

Source: 2019 AIME I #1

March 14, 2019
AMCAIMEAIME I2019 AMC2019 AIME I

Problem Statement

Consider the integer N=9+99+999+9999++9999321 digits.N = 9 + 99 + 999 + 9999 + \cdots + \underbrace{99\ldots 99}_\text{321 digits}. Find the sum of the digits of NN.