A gate has a standard key pad with the digits 0 through 9. How many possible code combinations are there if the code is 3 digits long.

Answer 1

nine things arranged 3 at a time, order matters
that is "permutations"
n! / [ n-r] !
n = 9
r = 3
n-r = 6
so = 9*8*7*6*5*4*3*2*1 / 6*5*4*3*2*1
so = 9*8*7

Answer 2

Whoops sorry TEN things
You can fix it

Answer 3

10*9*8