As you may have noticed in Try This 5, writing out all the factors can take a long time. Here is another way you could simplify 
Expanding the numerator and denominator gives you
As you can see, the expression in the brackets is the same as 9!. Therefore, you can write 
as 
Dividing the numerator and denominator by the common factor of 9! leaves 12 x 11 x 10, or 1320.
