One day, River writes down the numbers \(1, 2, ..., 999.\) What is the sum of all the digits that River wrote down?
"deleted"
But this is the sum of digits, not numbers
The sum of all the digits is 19998.
The sum of all digits: 1 + 2 + 3 + 4 +.............+ 9 + 9 + 8 + 9 + 9 + 9 = 13,500 - sum of all digits from 1 to 999 inclusive.
