Aaron is at a spot in his book where the page numbers of the two facing pages have a product of 1980 what are the two page numbers

Basically you know that they are 2 consecutive numbers whose product is 1980. 
n*(n+1)=1980 
n^2 + n - 1980 = 0 
(n -44)(n + 45)= 0 
n=44 
so the 2 page numbers is 44 and 45. 

The faster way is just to take the square root of 1980 and since that is 44.497 you can conclude that the 2 numbers is below and above it (44, 45)