February 14, 2000
Problem of the Month

The Book Problem

It takes 852 digits to number the pages of a book consecutively.

How many pages are there?

How many times is the digit 7 used?

Solution to the Problem:

There are 320 pages in the book, and the digit 7 was used 62 times.

Pages	Digits
1 - 9	9 digits
10 - 99	180 digits
100 - 320	663 digits
320 pages	852 digits

           

Pages	Number of 7's
1 - 100	20 sevens
101 - 200	20 sevens
201 - 300	20 sevens
301 - 320	2 sevens

Correctly solved by:

1. Liz Cotter	Oak Hill, VA
2. Tom Marino	Winchester, VA
3. Richard Mocarski	Winchester, VA
4. Chris Moats	Winchester, VA
5. Bob Hearn	Winchester, VA

Send any comments or questions to: David Pleacher