Here is the exercise from the "Arithmetic" book (ISBN: 5-02-013764-2).
There are 1989 numbers had printed to enumerate book's pages. How many pages in book?
Honestly I decided to refresh my arithmetic knowledge at all but stuck with that problem. Here's my decision:
- there are 9 numbers to print for pages 1-9 (9 * 1);
- there are 200 numbers to print for pages 10-99 (100 * 2);
- 1989 - 209 = 1780;
- 1780 /3 = 593,3(3) - that is the problem
I clearly understand how simple it must be and maybe something is wrong with my brain. But please, tell me where I made mistake.