I like to give explanations of why you do what you do in math, rather
than just tell you how to do it.  So here is why we do what we do.  It
makes math a lots easier if you understand why you do what you do, not
just how to do it.



Break it down:







So therefore



Count the x's. there are 17 x's all multiplied together, so we
write that as 

So a shorter way than writing out all the x's that are multiplied 
together and counting them up, is to simply add up the numbers
4+6+7 getting 17.  Then you don't have to write out all the x's that
are multiplied and then count them.  Just add up the exponents.

Short way:

 

Edwin