If I understand correctly, the formula is:

Here's what I have:

First:

=

Easy enough. Now though...

Doing it that way comes up with wildly incorrect answers. I'd type it out but it's just all wrong. The answer in the book is...

However, doing...

does get me

So that's really

So my question is: Why? I'm missing something in the translation and I'm hoping to get some kind of answer. Thanks for any and all help.