posted by Jimmy .
Brandon is reading a book Flatland and notices that the product of the numbers of the two pages his book is open to has a units digit of 6. What is the units digits of the sum of the two pages numbers?
since the page numbers must be consecutive,
the two pages can only end in 2 and 3
e.g. 52 and 53 ---> 2 x 3 = 6
so the sum must end in 5
e.g. 52+53 = 105