What does ! mean in an equation?

Question

ex)
3! + (6*5) - (5+0)= 31
Well 3! has to equal 6

Answer 1

4!= 4*3*2*1
! means factorial

Answer 2

Your a mathematician just another one of my tests.

Answer 3

Do you understand, Bridgett? You just multiply that number through 1. Examples: 8!=8*7*6*5*4*3*2*1, 3!=3*2*1, 12!=12*11*10*9*8*7*6*5*4*3*2*1.

Answer 4

3!=6

3!+(6*5)-(5+0)= 31

6+30-5=36-5=31