Why do we need these rules?  Let's go back to an old example from rule #2:

Look at this carefully...  It makes sense, doesn't it?  The problem was that the -2 exponent was confusing...  So, we need a way to deal with it.

Check out an example with just numbers:

TRY IT:

One of the games we'll be playing is to rewrite things so that there are no negative exponents.

Check it out:

                      This negative is not effected!