# In how many ways can you arrange 5 books in a bookshelf?

Feb 18, 2015

5! =120

For the first place in your bookshelf, you can choose any of the 5 books. For the second place you have a choice of 4, etc.

The total number of possibilities are thus:

$5 \cdot 4 \cdot 3 \cdot 2 \cdot 1$ which in maths is abbreviated to 5!
(pronounced as 5 factorial).

n! or "n-factorial" means: multiply all numbers from 1 up to and including $n$

Most calculators have an x! button. In GC's it's in one of the menus.