Question 268193
Two pages that are back-to-back in this book have 203 as the sum of their pages.What are the page numbers?

Let x and x+1 be the two page numbers.  Then we have:

x + (x+1) = 203
x + x + 1 = 203
2x = 203 - 1

Solve the above for x. Then the other page number is x+1.