1 to 100 how many digits?
If we write down the numbers from 1 to 100, we need to use 192 digits: one each for the number from 1 to 9, two each for each of the ninety numbers from 10 to 99, and three for the number 100. How many of these digits are zeros? The digit zero appears only in the numbers 10, 20, 30, 40, 50, 60, 70, 80, 90, 100.