A fifth-grade olympiad problem about book page numbers.

Obviously, the last page is three digits. Change 1 bit (9 bits) and two bits (90 bits) into three-digit codes. If 1 is changed to: 00 1.

9 changed to: 009, 10 changed to 0 10, and 99 changed to 099.

Then this book * * * has 834+2*9+ 1*90=942 codes.

It's page 942÷3=3 14. (not page 4 17)

From page 1 to page 3 14, check it in chapters:

1 to 99, the unit 1 of 10, the tenth 1 of 10, * *10+/kloc-0 = 20.

From 100 to 199, there are 10/0 10/0 100 100 * * 60.

From 200 to 299, one has 1 10, and the tenth has 1 10, * * *10+/kloc-0 = 20.

From 300 to 3 14, 1 has 2 units, 1 has 5 units, ***2+5=7 units.

So this book 1 uses 20+ 120+20+7= 167.