Question
How many digits are required to write first 500 natural
numbers?Solution
Single digit numbers are from 1 to 9 so in that total digits used = 9. From 10 to 99 there are 90 numbers of 2 digits , so here digit used = 90
2 = 180. From 100 to 500 there are 401 numbers of 3 digits  = 3
401 = 1203 (as all are of 3 digit number). So number of digits required to first 500 natural number = 9+180+1203 = 1392