math
posted by Lesly on .
The seventh book in the Harry Potter series has 759 pages. How many 2s were used when typing the page numbers?

From 0 to 99, there are 2*10=20 2's.
from 100 to 199, there are 20 2's.
...
from 600 to 699, there are 20 2's.
From 700 to 759, there are 204 2's.
How many 2's are there in all?