Question

sum of all digits used in writing numbers from 1 to 100

Answer 1

a is not present in all digits of numbers

Answer 2

In total, that is 1*9=9 digits. The numbers 10–99 have 2 digits each. In total, that is 2*90=180 digits. Lastly the number 100 has 3 digits.

i hope it help u....