We can model this with the equation: <em>a(1) + b(2) + c(3) = 720</em>, where <em>a</em> is the amount of 1-digit numbers, <em>b </em>is the amount of 2-digit numbers, and <em>c</em> is the amount 3 digit numbers that can fit with 720 digits of page numbering. We get <em>a = 9, b = 90, and c = 177</em>. So, we now add the 3 numbers.9 + 90 + 177=276, so there are 276 pages in the book.
