As a parent, I am confused as to how to write expressions. We are using the McGraw Hill Mathematics book (2002) for 5th grade. I understand the order of operations (PEMDAS) but am very confused how to evaluate the expression for value given. Example: 125 - x + 13 for x = 43 or 200 + 32 X a for a =20. Can you help me describe this to my son in easier terms and how to do it? How is the work done to arrive at the answer? Thanks for anything you can do.