If N is the sum of all digits used in writing all the numbers from 1 to 1000, then the last digit of N is

Find the mode of all digits used in writing the natural numbers from 1 to 1000.

The sum of all the 3 digit numbers is

Let N be the number of 4 digit numbers formed with at most two distinct digits.Then the last digit of N is

How many digits in all are required to write numbers from 1 to 124?

Let N be the number of 6-digit numbers such that the digits of each number are all form the set {1, 2, 3, 4, 5} and any digit that appears in the number appears atleast twice. Then the last digit of N is:

Sum of digit in the sum of all integers from 1 to 1000 inclusive which contain at least one 7 in their digits i.e.7+17++979+987+997= N.

What is the sum of all three digit numbers formed by using the digits 1,2,3,?