Formula for Pay Changes in Word

Okay, so I never knew you could do formulas in word. That means, I'm a complete novice. I've found the formula icon, but I don't know how to accomplish what I want to accomplish. I have three boxes that I need to pay attention to. Current salary, New Salary, and Pay Change %.

I need the pay change % to be a formula based on the Current Salary box and the New Salary box.

Basically this formula:

=(New Salary/Current Salary)-1


I also need this formula in the Pay change Amount box:

=New Salary-Current Salary

My assumption is this is possible, but maybe I'm wrong?

Actually, I think I might have figured it out. I use the formula icon, input this (this is from the original document, not the test):
{=(b8/b6)-1}

Now the question is, how do I make the formula update when I add new values in the current/new salary field?

Figured this out too - highlight table and F9