What if we have the eight books... But, we can only put three of them on the shelf? How many arrangements are possible?
Let's figure it out!
** It's ALWAYS better to think than to just try to slam through a memorized formula!
Here are the books and the slots:
How many choices do we have for this slot?
Let's say we put book C in slot 1... How many choices are left?
How many are left?
That wasn't bad at all!
If you have 10 books and you want to arrange 4 of them on a bookshelf, how many ways can you do it?