Evaluate each expression.

6! =

3!. 21 =

11

here we work with factorials, so if we have a whole number N, then:

N! = N * (N-1) * ... * 2*1

then, for the given expressions we have:

1) 6! = 6*5*4*3*2*1 = 720.

2) 3!*21 = (3*2*1) * 21 = 216

3) and the last expression seems incomplete, i guess this is:

11! = 11*10*9*8*7*6*5*4*3*2*1 = 39,916,800