1234
of 4

Factorials!

Let's reduce this thing:

8! / 5!

No, it ISN'T 3!

Write out what each means...

8! / 5! = ( 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 ) / ( 5 * 4 * 3 * 2 * 1 )

 

Now simplify:

8! / 5! = ( 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 ) / ( 5 * 4 * 3 * 2 * 1 ) ... the 5 * 4 * 3 * 2 * 1 cancels out ... = 8 * 7 * 6 = 336 ... done!
You can use your calculator for this.

 

YOUR TURN:

Reduce

6! / 4!