As Jack finished a section of the novel he was reading, his wife posed a curious question: "Dear, suppose you took the page numbers of the section you just read and added them together. What would you get?
Jack summed them rather hastily and said, "Well, I may have to double-check my arithmetic. It's either 412 or 512, I'm not sure.
Which is it and why?
The answer is 412.
The logic is that the totals of the first and last pages must be an odd figure, ...
A word problem is solved by appying sums of odd and even numbers.