How many eights are there in the numbers from 8 to 100?

Answer 1

20

Each of the numbers 8, 18, ... 98 has an 8 in the units digit. That's 10 8's.

Each of the numbers 80, 81, ... 89 has an 8 in the tens digit. That's 10 more 8's.

(You could do this yourself just by writing down all the numbers.)