Question 2
A 2020-digit number begins $123456789101112\cdots$. Find the remainder when it is divided by 9.
Editorial clarification: concatenate the positive integers 1, 2, 3, ... in order and stop after exactly 2020 digits, even if the final integer is incomplete.
Editorial clarification: concatenate the positive integers 1, 2, 3, ... in order and stop after exactly 2020 digits, even if the final integer is incomplete.