Suppose that I have 6 different books, 2 of which are math books. In how many ways can I stack my 6 books on a shelf if I want a math book o

To elaborate on Melody's answer....we can have either math book at both ends...so that's two ways to arrange those.

And, in the "middle,' the other 4 books can be arranged in 4! = 24  ways.

So   ..   2 x 4!  = 2 x 24  = 48 ways 

2*4! =

$${\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{4}}{!} = {\mathtt{48}}$$

Thanks Chris,

You are right I do not explain these types of answers very well.  Thanks for the extra explanation.  :)