Question 487294
The symbol ! after a number is called "factorial"
For instance, 9! is called "factorial 9"
What you do to find the value of factorial 9 is
to multiply all the digits from 1 to 9
{{{ 1*2*3*4*5*6*7*8*9 = 9! }}}
BY my calculator, this is:
{{{ 362880 = 9! }}}
Factorials are used a lot in probability and
combination problems, like
" How many different ways can 5 people be
seated in 5 chairs?
{{{ 1*2*3*4*5 = 120 }}} different ways
That's quicker than writing down all
the possible ways.